’

A DISCOURSE ON THE METHOD

R D was born at La Haye near Tours on March. He was educated at the Jesuit Collège de la Flèche in Anjou,and at the University of Poitiers, where he took a Licenciate in Lawin . Two years later he entered the army of Prince Maurice ofNassau in Holland, and met a local schoolmaster, Isaac Beeckman,who fostered his interest in mathematics and physics. After furthertravels in Europe he settled in Paris in , and came into contactwith scientists, theologians, and philosophers in the circle of theMinim friar Marin Mersenne. At the end of Descartes left forHolland, which he made his home until ; he devoted himself tocarrying forward the mathematical, scientific, and philosophicalwork he had begun in Paris. When he learned of the condemnationof Galileo for heresy in , he abandoned his plans to publish atreatise on physics, and under pressure from his friends consentedto have the Discourse on the Method printed, with three accompany-ing essays on topics in which he had made discoveries. In hisMeditations appeared, setting out the metaphysical underpinningsof his physical theories; these were accompanied by objections writ-ten by contemporary philosophers, and Descartes’s replies to them.His writings provoked controversy in both France and Holland,where his scientific ideas were banned in one university; his works,however (including the Principles of Philosophy of ) continuedto be published, and to bring him notoriety and renown. In heaccepted an invitation from Queen Christina of Sweden to settle inStockholm; it was there he died of pneumonia on February .

I M is Professor of Renaissance Studies at theUniversity of Oxford and a Senior Research Fellow of All SoulsCollege. Among his publications are The Renaissance Notion ofWoman (, frequently reprinted), Meaning and Interpretation inthe Renaissance: The Case of Law (), Montaigne philosophe(), Logic, Signs and Nature in the Renaissance: The Case ofLearned Medicine (), and an edition of Cardano’s De librispropriis ().

’

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OXFORD WORLD’S CLASSICS

RENÉ DESCARTES

A Discourse on the Methodof Correctly Conducting

One’s Reason andSeeking Truth in the Sciences

Translated with an Introduction and Notes by

IAN MACLEAN

1

3Great Clarendon Street, Oxford

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Descartes, René, 1596–1650.[Discours de la méthode. English]A discourse on the method of correctly conducting one’s reason and

seeking truth in the sciences / René Descartes ; translated with anintroduction and notes by Ian Maclean.

p. cm. –– (Oxford world’s classics)Includes bibliographical references and index.

1. Methodology. 2. Science––Methodology. I. Maclean, Ian. II. Title. III. Oxford world’s classics (Oxford University Press)

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1

CONTENTS

Acknowledgements vi

Introduction viiA Philosopher’s Life viiiThe Genesis of the Discourse and its Development xxiiiGalileo, Mersenne, and the Church: Authority and Truth xxviiiThe Publication of the Discourse xlThe Discourse xliv

Part Six: the Presentation of the Project xlvParts One and Two: Intellectual Autobiography xlviiiParts Two and Three: Precepts in Philosophy and Ethics xlixPart Four: Metaphysics and Epistemology liiiPart Five: Physics and Physiology lviiiThe Essays Published With the Discourse: Dioptrics,

Meteorology, Geometry lxDescartes As a Writer lxiiiEnvoi: The Cartesian Philosophical Edifice lxix

Note on the Text lxxi

Select Bibliography lxxii

A Chronology of René Descartes lxxiv

A DISCOURSE ON THE METHOD

Part One Part Two Part Three Part Four Part Five Part Six

Explanatory Notes

Index

ACKNOWLEDGEMENTS

I should like to record my gratitude for the kind assistance I receivedfrom the following colleagues and friends: Robin Briggs, JohnCottingham, Dan Garber, Noel Malcolm, Michael Moriarty, andRichard Parish. I am also very grateful for the support andencouragement I received from Judith Luna of Oxford UniversityPress.

INTRODUCTION

The publication in of an anonymous book in French entitled ADiscourse on the Method of Correctly Conducting One’s Reason andSeeking Truth in the Sciences marks one of the pivotal moments ofWestern European thought; it was the work of a formidably clever,radical, rigorous thinker, who in this short, informally presentedintroduction to his work threatened the very foundations of manyprevailing philosophical beliefs, and set an agenda for enquiry intoman and nature whose effects have lasted up to the present day. Inthis introduction to his thought, Descartes set out his novel philo-sophical and ‘scientific’1 programme, and prepared his contemporar-ies to receive it, even though they would be looking at it through theprism of their intellectual expectations, which (for the learnedamong them) had been formed in the traditional framework of Aris-totelian philosophy and its characteristic modes of debate. It is, ofcourse, impossible fully to re-create the sense of reading a work forthe first time, especially one written so long ago, and in so different acultural climate; as Bernard Williams pointed out in , we canplay seventeenth-century music from seventeenth-century scores onseventeenth-century instruments, but we will hear it with twentieth-century ears.2 But even though any attempt at reconstruction will bea pis aller, I shall nonetheless adopt a historical rather than timelesslyphilosophical approach to the text, and seek to place it in contexts

1 I shall use ‘science’ and ‘scientific’ in this introduction to designate what Descarteswould have known as ‘natural philosophy’, that is, the pursuit of causal knowledge in theinvestigation of nature. While it is generally agreed that the map of disciplines was verydifferent in Descartes’s time from what it is now, there has been much recent debate asto whether a continuity can be perceived from the natural philosophy of the seventeenthcentury to modern science; by the use of inverted commas, I intend to signal a potentialanachronism, but not to take a side in this debate, for an account of which see EarlyScience and Medicine, (). The numbers in brackets throughout the Introductionrefer to volume and page in the standard edition of the complete works of Descartes byCharles Adam and Paul Tannery, vols. (Paris, ): hereafter referred to as AT inthe text and notes.

2 Descartes: The Project of Pure Enquiry (Harmondsworth, ), .

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which reveal something of its early impact. I have not attemptedcomprehensively to cover the whole range of meanings which havebeen attributed to the Discourse; my aim is to set it in the contextof the life of its author, to give some inkling of what Descarteshimself was setting out to achieve by its publication, to indicate howhe came to put its various components together and make it availableto the public, and to suggest what its first readers might have madeof it.

A Philosopher’s Life

René Descartes was born on March at a village called LaHaye in the French province of Poitou (a token of his posthumousprestige was its renaming as La Haye-Descartes in ; since his birthplace has been known just as Descartes). His father was amagistrate in Brittany; through his profession he possessed thestatus of nobility, being a member of the so-called ‘noblesse de robe’.This class was resented by the old military nobility (the ‘noblessed’épée’), who looked on lawyers as little more than pen-pushers;but those who enjoyed the status set great store by it. They were notabove inflating their claims to aristocracy by acquiring lands whichconferred on them titles (‘terres nobles’), and even putting onmilitary airs; such was the case with the otherwise admirablyunpretentious Michel de Montaigne (–: a figure important toDescartes in more than one way, as we shall see), whose grand-parents were merchants, whose father was an army officer, and yetwho felt able to boast that he was the ‘scion of a race famous for itsmilitary valour’. On both sides of his family, René’s forebears hadbeen doctors and lawyers, prosperous enough to acquire ‘terresnobles’ for members of their families. René’s title, which he useduntil his mid-twenties, was du Perron: he was known by this title byhis Dutch acquaintances in the early s. The sense of statuswhich this background gave him was a motivating force in his laterlife.3

3 See Ellery Schalk, From Valor to Pedigree: Ideas of Nobility in France in theSixteenth and Seventeenth Centuries (Princeton, ); Montaigne, Essais, ed. Pierre

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As Descartes tells us himself, he was a sickly, pale-complexionedchild, who suffered from a dry cough (AT . –); he was broughtup in his grandmother’s house, his father being absent in Brittany,having remarried in . In he was sent away from home to beeducated, to the newly founded Collège de la Flèche; this was aJesuit school, which like others of its kind was established to servethe needs of the professional classes and nobility, as well as to pro-duce Jesuit priests and missionaries. Its second principal, FatherÉtienne Charlet (–), was related to Descartes’s mother’sfamily. Perhaps through this connection, and because of his delicateconstitution, a concession was made: René was allowed to get uplater in the morning than the other pupils, a practice to which headhered for much of his life (in contrast to the ascetic and exactingregime of contemporary scholars, who often rose in the early hours,worked by feeble candlelight, and ruined both their eyesight andhealth in the process).

The Collège had an impressive and rigorous curriculum, whichincluded the university arts course (the so-called trivium of gram-mar, logic, and rhetoric, and quadrivium of arithmetic, geometry,music, and astronomy), which was taught as a preparation fordegrees in the higher faculties of theology, law, and medicine. Thiscurriculum had been codified and published by the Jesuits in ,in its Ratio studiorum: it integrated what are now known as thehumanities (classical literature, history, drama, and so forth) withscholastic philosophy and theology. The Ratio had all of the benefitsand all of the defects of such codifications; while it set high stand-ards, it also discouraged innovation, especially in the investigation ofnatural philosophy. Descartes provided an account of the curriculumin the Discourse: he was given a thorough grounding in ancient lan-guages and literatures, grammar, logic, and rhetoric, and instructedin scholastic natural philosophy, mathematics, metaphysics, and eth-ics. Descartes reacted very differently to these two components. Onthe one hand, he commented adversely on the logic and philosophy

Villey (Paris, ), . , p. : ‘la fortune m’a faict naistre d’une race fameuseen preud’homie’; for use of the title du Perron, see Isaac Beeckman, Journal à , ed. Cornelis de Waard, vols. (The Hague, –).

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he was taught, with its rebarbative vocabulary, inelegant syntax, andold-fashioned forms of writing and learning (disputations and‘quaestiones’), although it should be pointed out that he did notentirely lose his taste for it: one or other of St Thomas Aquinas’s twovoluminous theological Summas was a book he took with him––another being the Bible––when he moved to Holland from Paris inthe late s. On the other hand, the strong emphasis on human-istic learning and elegance of expression was to turn him into astylish and fluent writer of Latin. Jesuit schools have long beenassociated with the claim: ‘give me the child, and I will give you theman.’ In the atmosphere of Counter-Reformation Europe, it mightwell be thought that this would entail the inculcation of an intransi-gent religious outlook founded on unswerving obedience to theRoman Church. There is clear evidence, as we shall see, that Des-cartes was very reluctant to be seen to oppose this body, even whenhe secretly believed it was wrong, as in the case of the condemnationof Galileo. In this, he may even have kept in his mind the stricture tobe found in the Spiritual Exercises of the founder of the Jesuit order,St Ignatius Loyola (?–): ‘to be right in everything, we oughtalways to hold that the white which I see, is black, if the HierarchicalChurch so decides it.’ He may indeed have heeded this advice overmatters of ‘science’, but he seems not to have taken from his school-ing a personal hostility to Protestants; many became his friends and‘scientific’ colleagues, and he himself chose to settle in a Protestantcountry characterized by the relatively tolerant co-existence there ofvarious religious groups.4

Descartes stayed at the school until ; he then went on to theUniversity of Poitiers, where, in , he took a Licentiate in Law(a higher degree, academically very nearly the equivalent of the

4 See Stephen Gaukroger, Descartes: An Intellectual Biography (Oxford, ), –(there are many biographies of Descartes, which all share a great deal of the samematerial; this one is very well documented); AT . (reference to the Bible and theSumma); St Ignatius Loyola, Ejercitios espirituales, cuarta semana, a regla, in Obrascompletas (Madrid, ), : ‘debemos siempre tener, para en todo acertar, que loblanco que yo veo, creer que es negro, si la Iglesia hierárchia assi lo determiná’; onDescartes’s strong reservations about disputations, see the preface to the French editionof the Principes, AT B. –. On Descartes’s view of the Netherlands as a place of ‘suchtotal liberty’, see AT . .

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doctorate). This was no doubt at the behest of his father, who mighthave hoped that he would follow him in his profession. He may alsohave studied medicine in these years; he appears at some stage tohave acquired some skill in dissection. He did not, however, take upthe law, but instead went to Holland in , where he joined thearmy of the Protestant Prince Maurice of Nassau. It is not knownwhat role he fulfilled in the armies to which he was attached: hisbiographer Adrien Baillet (–) suggests it was that of engin-eer, involved with military architecture and fortifications, but hemight equally have undergone a form of training as a gentlemansoldier. This was not a surprising choice of career for a member ofthe minor nobility (nor was it unusual to join armies representingconfessional interests other than one’s own, providing that there wasno clash of national interest); throughout his life Descartes was toremain conscious of his status as a gentleman, and some of hisattitudes to scholarship and publishing are tinged with an aristo-cratic disdain for trade. Through his inheritance from his mother,who had died in , he eventually acquired an annual income.This was assessed by one of his early biographers at about ,–, livres: a modest sum, but sufficient to ensure independentliving, provided that one avoided too many extravagances. Descartesseems to have been naturally frugal; he did not maintain a largeretinue, ate and drank in great moderation, dressed in a sober fash-ion, and avoided socializing––to which, in any case, he was littledrawn: on May he confided to his friend Jean-Louis Guez deBalzac (–), in a letter (AT . ), that in Amsterdam hepaid no more attention to the people he met than he would to thetrees on his friend’s estate and the animals that browsed there.There is no indication that he suffered financial difficulties until thelast few years of his life. Baillet suggests that he was actually richerin the late s than ever before, but his behaviour seems to indi-cate the reverse; he speaks in letters for the first time of beingwilling to accept patronage (to Hector-Pierre Chanut, November, AT . ), something which he had steadfastly refused tocontemplate up to then.

While in Breda in he met a schoolmaster and mathematician,Isaac Beeckman (–), who was to be one of the formative

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influences on his intellectual development. Until he was infairly regular contact with Beeckman; a significant cooling of theirexchanges then occurred, due to Descartes’s accusation that Beeck-man had been boasting about what Descartes had learned from him,which led to the ungracious demand that the musical treatise he hadgiven to Beeckman as a present be returned. Although there was arapprochement, they never were as close friends again. This was notthe only time that Descartes was to fall out with close associates, onlylater to be partially reconciled with them. One of his biographersrefers to the years – as Descartes’s ‘apprenticeship withBeeckman’; in fact, Beeckman was not as good a mathematician asDescartes, but was more up-to-date with practical problems inmechanics, and better instructed in natural philosophy. They dis-cussed (often with Beeckman supplying the question and Descartesthe answer) the nature of matter, mechanics, hydrostatics, optics,acoustics, and gravitation; from these exchanges Descartes com-posed his first work, a short treatise on music entitled Compendiummusicae, which was completed in December and presented toBeeckman.5

In the meantime, Descartes had left the army of Maurice ofNassau and had joined that of the Catholic Elector Maximilian, dukeof Bavaria, in Germany, where he was present at the coronation ofthe Holy Roman Emperor Ferdinand II at Frankfurt in September. Later in that year he found himself in winter quarters, nearUlm according to some, or Neuburg according to others;6 and on November (as Baillet tells us), shut up in a stove-heated room, heexperienced three dreams which profoundly influenced the course ofhis life. He refers to these visions obliquely in the Discourse; but thedetails of the dreams were known only after his early papers werecirculated posthumously (AT . –). He had spent the daymeditating on the ‘foundations of a wonderful science’, and it was inthe context of this ambitious and all-embracing project that heinterpreted his dreams. In the third of these, he was confronted with

5 Adrien Baillet, La Vie de Monsieur Descartes (Paris, ) .– (on income);Gaukroger, Descartes, –, –.

6 Geneviève Rodis-Lewis, Descartes: His Life and Thought (Ithaca and London,), .

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a pregnant question (a line remembered from the classical writerAusonius): ‘what road in life shall I follow?’ There have been manyattempts to explain the psychological processes revealed by hisaccount of this event: for some, it expresses a young man’s disquietabout the intellectual presumption implicit in his proposed enquiriesinto nature; for others, it is a sign of a nervous breakdown, or even abad migraine. It is noteworthy in respect of this early experience thatin his later published writings he never referred to dreams as bearersof spiritual messages, but considered them as no more than corporealin origin and subject to error; but there is one reference in a letter ofNovember to ‘following one’s inner inclinations’ (AT . )which may suggest that dreams could be taken seriously. If so, thepossibility might also be entertained that the event imbued him witha sense of a divinely inspired mission; it was his destiny to pursue the‘wonderful science’ and reveal it in due course to his contemporaries.He could not, of course, do this by referring to the heavenly directivehe had received in this numinous way, especially as he was put off byany whiff of occultism; the current vogue for alchemy and magic,with its obscure and secretive lore revealed only to initiates, repelledhim (AT . , . ). So the works he eventually published scru-pulously exclude any reference to mysteries and to knowledge avail-able only to initiates, and rigorously eschew all mental activitiesexcept those which could be ascribed to a thinker exploiting thenatural light of his reason.7

Inspired by this vision, but also by work he had already begun, hecomposed over the next decade a work which was published post-humously with the title Rules For the Direction of Our Native Intelli-gence (Regulae ad directionem ingenii); this confirms that from an earlydate he was interested in formulating a general method for ‘scien-tific’ enquiry. His movements at this period of his life are difficult toascertain. It is not known when he ceased to be a soldier. Baillet tellsus that he returned to France in ; it is known that in May of thatyear he sold the property through which he held the title du Perron

7 Baillet, Vie, . ; Ausonius, Eclogarum liber, : ‘Quod vitae sectabor iter?’;Les Olympiques de Descartes, ed. Fernand Hallyn (Geneva, ); Gaukroger, Descartes,–.

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with its seigneurial rights; it seems likely that he set out for Italy atsome point in , and while there visited the shrine of Our Ladyof Loreto, which, according to one early biographer, he had solemnlyundertaken to do immediately after his dreams in (anotherindication, perhaps, if it is true, that he saw the dreams in terms of adivine directive). By he was again in Poitou, where he flirted forthe last time with the idea of taking up a legal career; he then trav-elled on to Paris, to remain there until . This was a tense time inthe capital: the vogue for allegedly lax morality among young gentle-men, connected with the production of libertine (in part obscene)literary works and publicly expressed indifference (if not worse) toreligion, had led to a number of thunderous denunciations of athe-ism and free-thinking, and the trial of the prominent poet Théophilede Viau (–). Descartes makes one brief reference to thisatmosphere and to the free philosophizing associated with it in aletter to Mersenne dated May (AT . ), and quotes once ina letter of February from a poem by Théophile (AT . );but there is no reason to believe that he ever was beguiled by free-thinking, or to doubt the sincerity with which he upholds his ownpersonal religious belief and his determination to find arguments torefute deists and atheists.8

He consorted in Paris with two former pupils of the Collège de laFlèche (although there is no evidence that he knew them while atschool): Claude Mydorge (–), a gentleman of leisure andindependent means, who like Descartes devoted himself to ‘scien-tific’ problems; and Father Marin Mersenne (–), a Minimfriar, who was already a well-published author on theology and itsrelation to natural philosophy, an implacable enemy of free-thinkers,and an indefatigable correspondent of the learned communitythroughout Europe. Until his death in , Mersenne was toremain Descartes’s mentor and principal contact in the capital. Hecame to know other important figures in the ‘scientific’, literary, andreligious communities, including Jean de Silhon (–), who,like him, was to write as a lay person on the soul; Father Guillaume

8 Gaukroger, Descartes, –; Antoine Adam, Les Libertins au XVIIe siècle (Paris,).

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Gibieuf (?–), through whom he was later to seek accept-ance by the theological community of Paris; the stylist and epistolarywriter Jean-Louis Guez de Balzac; a fellow mathematician andphysicist, Étienne de Villebressieu (d. ); the librarian and anti-quary Gabriel Naudé (–); and Jean-Baptiste Morin (–), whose broad range of interests included astrology. In thesecircles he quickly obtained a reputation as a powerful and originalthinker; during his association with them, he discovered the sine lawof refraction in optics (which had been independently discovered byother mathematicians at about this time, and is now known as Snel’sLaw), and came to learn of Mersenne’s interest in mechanics and hismathematical approach to nature. He would also have heard dis-cussed some of the most innovative modern thinkers, such as FrancisBacon (–), whose New Organon, or True Directions For theInterpretation of Nature (Novum organum, sive indicia vera de inter-pretatione naturae) had appeared in . He pursued the question ofthe certainty of mathematics, in order to warrant its use as a guidingdiscipline in physics; this seems to have led to disappointment on theone hand, and, on the other, a desire to extend the project of findingcertainty into a much broader field (a desire encouraged by theinfluential Counter-Reformation cleric Cardinal Pierre de Bérulle(–), who had been present at a meeting at which Descartespowerfully refuted a proponent of chemical philosophy, and wasimpressed by him). By late he put into execution his plan toretire from Parisian intellectual life, stimulating though it was, andlive in the Netherlands, which was to be his home (with frequentchanges of address) for the next twenty years. It was there, in ,that he entered into a relationship with a maidservant known only toposterity by her first name, Helena; she had a daughter by him, bornon July , whom he recognized as his. The child’s death in seems to have caused much distress to Descartes. He alsoentered into contact with the Dutch diplomat and polymath Con-stantijn Huygens (–), who was to help him in his relationswith the Dutch court.9

The broader project on which Descartes set to work (sometimes

9 On all the friends and contacts mentioned above, see Gaukroger, Descartes, –.

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referred to by his correspondents as his ‘Physics’) was given by himthe title The Universe (Le Monde), and was to be an ambitiousaccount of the physical world on mechanistic principles. Most of twoparts of this work survived (the Treatise on Light and the Treatise onMan), and were found among his papers after his death; the thirdpart, on the soul, was not found, and may not have been written. Atthe same time, we learn from a letter which Guez de Balzac wrote tohim on March (AT . ) that he was planning an auto-biographical essay entitled ‘the story of my mind’ (L’Histoire de monesprit). He also had by this time sketched out a set of metaphysicaland epistemological essays which were transformed into the Medita-tions of . But disaster was to strike. The Universe was predicatedon a Copernican cosmology, which had already been censored by theInquisitors of the Roman Church in ; seventeen years later itwas officially and very publicly condemned in the same body’sjudgement on Galileo’s Dialogue Concerning the Two Chief WorldSystems. Descartes immediately abandoned his plans to publish TheUniverse. He had never been very keen on the idea of publication,not only for the snobbish reasons suggested above––that it smackedof trade––but also because he was very protective of his privacy: as atoken of this, his adopted motto was the adage of Ovid, bene quilatuit, bene vixit (he who remains well hidden, lives well: AT . ).His Parisian friends pressed him, however, to make his philosophyknown, and succeeded in inducing him to compose the Discourse onthe Method of Correctly Conducting One’s Reason and Seeking Truth inthe Sciences, and to set down his achievements in optics, meteorology,and geometry. These works appeared in French in ; theyincluded an invitation to the learned world to respond to them bysending critiques to Descartes’s publisher, who would forward themto the author for consideration and reply. He declared himself keento engage in discussion this way, rather than in public disputation,because he believed that the latter mode of debate encouraged parti-cipants to win at any cost, rather than pursue the truth for its ownsake (AT B. –). In fact, the suggestion did not bear fruit as he mayhave hoped in this case, although it did a few years later in the case ofthe Meditations, which were published with objections and replies.

Having once embarked on the career of author, Descartes saw

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himself obliged to continue, if only to avoid misrepresentation byothers (something about which he was very sensitive). In the Meditations on First Philosophy, Together With the First Six Sets ofObjections with Replies appeared in Latin; a second, enlarged, volumecame out a year later, and a French translation by the duc de Luynes,to which Descartes gave his approval, followed in . TheMeditations, whose first-person singular is not so much the historicalDescartes as it is any reflective person working their way through aset of arguments, do not describe philosophical discoveries, butpresent them in the order in which readers are enjoined to enactthe process of discovery for themselves. In this they are unlike theDiscourse, which is presented as a personal and historical narrative.In his Latin Principles of Philosophy followed; three of its fourbooks are about ‘science’ (physics and natural philosophy) ratherthan strictly philosophical principles. It was published in French in in a translation by Abbé Claude Picot (?–), a Parisianpriest who was converted to Descartes’s philosophy by theMeditations, and who came as a friend to look after Descartes’s finan-cial affairs in the last years of his life. Also in a Latin version ofthe Discourse appeared, which made this text accessible to the widerlearned community. Other writings followed, often in response tocriticisms of his work, for by the early s Descartes had becomenotorious throughout Europe; these included the Comments on aCertain Broadsheet (Notae in programma quoddam), which appearedin . Descartes’s philosophy (or rather, a version of it which hedisowned) had been enthusiastically adopted by his disciple Henrickde Roy (Regius) (–), of the University of Utrecht; the rec-tor of that same Calvinist establishment, Gijsbert Voet (–),had it condemned there in . Regius was the author of the broad-sheet which provoked the Comments of , in which he set out aversion of Cartesianism unacceptable to Descartes, who very muchresented being drawn into such controversies; he looked upon themas distractions from his true vocation, which was to develop hissystem in order eventually to provide a secure grounding for ethicsand medicine. He himself had also hoped that his philosophy mightbe adopted by the Jesuits for use in their colleges; but as he ruefullytold Huygens in a letter dated January (AT . ), he found

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as many opponents in their midst as he did among the Protestants ofthe Low Countries.10

The last work to appear in his lifetime, in , was the Passions ofthe Soul (Les Passions de l’âme), written, like the Discourse, in French.This may well have been inspired by his contacts, beginning in ,with Princess Elizabeth (–), the Calvinist granddaughter ofJames I and daughter of the deposed king of Bohemia, who wasliving in exile in The Hague; in her correspondence with him, shehad pressed him to explain the interaction of soul and body in hissystem. He had already made explicit his decision to write accessibly,not only for members of the court but also for women; her lucid andshrewd questioning must have confirmed for him the wisdom of thisdecision.

By the financial stability which had allowed Descartes to liveindependently and to reject all offers of patronage seems to havebeen threatened. In that year he returned to Paris, to arrange to takeup the royal pension that he had been granted in that year––anexpensive procedure, involving the outlay of money to obtain a royalwarrant before any pension was received. The following year saw thebeginning of the civil wars in France known as the Fronde, whicheffectively put an end to royal patronage for half a decade (in spiteof Baillet’s claim to the contrary, it seems that Descartes was never toreceive a penny of royal largesse). It may have been such materialfactors that persuaded him to accept the patronage offered by QueenChristina of Sweden (–), who was actively seeking to sur-round herself with prominent scholars and thinkers. In , havingput his affairs in order, he set out with all his papers for Stockholm,dressed, to the astonishment of his acquaintances, in the clothes of afashionable courtier, with his hair in ringlets.11 After a rather unsatis-factory beginning to his stay there, during which he made some newFrench friends and was entrusted with some nugatory tasks, he waseventually summoned to the royal palace on Christina’s return to hercapital, to instruct her in his philosophy. She ordained that this

10 Gaukroger, Descartes, –.11 AT . has the description of Brasset, the secretary of the French Embassy at

The Hague.

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should take place from a.m. to mid-morning; the man with theweak chest, who had spent the greater part of his life rising late andnursing his health, was now exposed not only to the rigours of aStockholm winter in the early hours of the morning, but also to theinfectious pneumonia of his friend the French ambassador, Hector-Pierre Chanut (–), in whose residence he lived, and whosebedside he attended during his illness. Descartes in turn contractedpneumonia, and died on February .

Descartes’s correspondence, which was published soon after hisdeath, reveals something of the character of its author, as do his earlybiographers. Baillet, in a somewhat hagiographical account of Des-cartes’s life, describes him as a man with a serene and affable expres-sion, careful in his consumption of food and wine, content to keephis own company, without personal affectations or foppishness (heonly took to wearing a wig towards the end of his life, for reasons ofhealth). Baillet assures us that if he was at all vain, this was only asuperficial vanity; he was modest, indifferent to public acclaim, andhad a gift both for fostering the careers of those for whom he wasresponsible, and for the friendship of his peers. Among Descartes’smodern biographers, only Geneviève Rodis-Lewis has retainedmany of these features; she has also stressed his frequent changes ofaddress, and attributed them to his overriding desire to be left aloneto pursue his search for scientific and philosophical truth. His elu-siveness was noted even by his contemporaries: his acquaintanceClaude de Saumaise (–) wrote to a correspondent in that Descartes kept well away from others (‘à l’escart’) even in asmall town like Leiden, and wittily suggested said that his nameought to be spelt ‘D’escartes’ (AT . ); Descartes himself wroteon more than one occasion that he disliked having neighbours (AT .; . ). While conceding that he had a quick temper, Rodis-Lewis also points out that he was often generous with his time, andreceived even lowly visitors who came to consult him; and in spite ofhis conviction that animals were no more than machines (AT . –),he kept a dog called M. Grat (‘Mr Scratch’), of whom he may evenhave been fond.12

12 Baillet, Vie, –; Geneviève Rodis-Lewis, Descartes.

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The adage, ‘there is nothing more praiseworthy in a philosopherthan a candid acknowledgement of his errors’––advice offered byDescartes to Regius in January (AT . )––would flow natur-ally from the pen of the Descartes described in Baillet’s biography;but it has struck others as out of character in a man who seems neverto have accepted the correction and critique of others. He never fellout, it is true, with his closest acquaintance Mersenne, although heoffended him on occasion, but with many other contemporaries hisrelationship ran into difficulties arising from his touchiness, his highassessment of his own work, his low assessment of the intelligence ofthose around him, and his fastidious and self-protective sense ofprivacy. One modern philosopher-critic has described him as ‘lofty,chilly and solitary’, cultivating ‘a certain reserve and self-sufficiencyin life and manner’;13 to these unendearing characteristics othershave added arrogance, a contempt for others which was not alwaysjustified, and a capacity to bully those he looked upon as inferior inintellect to himself. He instructed the long-suffering Mersenne totreat his adversary Jean de Beaugrand (?–) with contempt,and described his letters as fit only for use as lavatory paper; thework of Pierre de Fermat (–) was ‘dung’; mathematicianswho criticized his geometry were said to be ‘flies’; and although heinvited his contemporaries to criticize the Discourse and the worksthat followed it, those who took up his invitation came in for a greatdeal of contumely. Gilles Personne de Roberval (–) is said tobe ‘less than a rational animal’; Pierre Petit (–), ‘a little dogwho barks after me in the street’; Thomas Hobbes (–),‘extremely contemptible’ for daring to call his work into question;others who, having criticized him, did not accept his refutation ofthem, were described as ‘silly and weak’.14 Descartes was also notabove mystifying his correspondents, and making fun of them bysetting them difficult or incomplete mathematical problems (AT. ); he compounded this with an unwillingness to disclose hiswork to others (e.g. AT . –) which seems almost to make his

13 Williams, Descartes, .14 Gaukroger, Descartes, , assembles these comments.

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attack on alchemists and occult philosophers for their secretivenesshypocritical. Unsurprisingly, he had a low opinion of the vast major-ity of his readers, confiding to Mersenne that he did not believe themcapable of recognizing the truth of his arguments (AT . ). Ifthere is a feature which redeems to some degree such disagreeableattitudes and behaviour, it is Descartes’s honesty and integrity. Hemay have had an exaggerated sense of his own abilities, but (with thepossible exception of his snobbery and his silence over his senseof a personal prophetic mission), the account he gives of histhought-processes and his motivations is frank and scrupulous.

Descartes was buried in Stockholm; in it was decided thathis remains should be exhumed and returned to Paris, to rest even-tually in the abbey church of Sainte-Geneviève. At the exhumationthe French ambassador was allowed to cut off the forefinger ofDescartes’s right hand, and a captain of the Swedish Guards maywell have removed the skull and replaced it with another. Thisremoved skull was then traded several times, before ending up in thehands of the Swedish chemist Jons Jacob Berzelius, who in offered it to the palaeontologist Georges Cuvier; it is now to befound in the Musée de l’Homme in the Palais de Chaillot in Paris.The body, meanwhile, found its way eventually to the abbey churchof Saint-Germain-des-Prés, where it now lies.15

This dismemberment is emblematic of the posthumous fortunesof Descartes’s work and doctrine, parts of which have been taken upin different ways at different times, even if his philosophical and‘scientific’ doctrine was recognized as a coherent system in his life-time. By the adjective ‘Cartesian’ had emerged; it designatedprincipally his mechanistic philosophy. This was opposed not onlyby Aristotelian traditionalists, but also by other radical thinkers, andwas a powerful motor in the debate about the nature of matter andmotion, even if none of his physical theories is now looked upon ascorrect. At the same time, the Discourse had another, more diffuseeffect. Its radical programme, which did not require philosophicaland ‘scientific’ training but only the employment of ‘good sense’,appealed to those who had not received a formal education, notably

15 Ibid. –.

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women, who felt empowered by his promotion of the image of thewell-reasoning individual. By the mid-s, in Paris, ‘the free useof reason’ was associated with various radical views, some of themfeminist, and Descartes was seen as its champion and a liberatorfrom prejudice: ‘Cartesiomania’ broke out. He was also seen as adangerous radical in another way: his theory of matter posed prob-lems for the Roman Catholic doctrine of transubstantiation(although Descartes insisted that it did not: see AT . ; . ,; . –); in his works found their way onto the RomanInquisition’s Index of Forbidden Books, in the category of thosewhich needed correction before they could be published: asupremely ironic fate, given Descartes’s strenuous efforts not tooffend the Church.

Thereafter, Descartes developed into the national emblem of aspecifically French kind of rationalism, and was attacked ordefended as such in contradistinction to the empirical philosophy ofthe English. This opposition was fostered by early Enlightenmentthinkers such as Montesquieu and Voltaire (to the disadvantage ofDescartes). By the time of the French Revolution he had beenturned into a representative of republican thought, deserving of aplace in the pantheon of such French heroes; in the nineteenth cen-tury he came to be seen as a petit-bourgeois Catholic thinker, beforebeing appropriated by the French educational system and made intothe model of clarity of thought and good style in French. It is hardlysurprising, therefore, that in , on the three-hundred-and-fiftiethanniversary of the publication of the Discourse, a book appeared withthe title Descartes c’est la France.16

Across the Channel, meanwhile, in more recent times Descartes,has been heralded as an honorary practitioner of analytical phil-osophy, even in some ways its founding father; and although hisaccounts of the relationship of mind and body, or the existence ofother minds, or that of possible other worlds are seen as flawed, hehas set the agenda for a certain sort of philosophical training, and thestandard for rigorous introspective philosophical speculation. His

16 See Stéphane Van Damme, Descartes: essai d’histoire culturelle d’une grandeurphilosophique (Paris, ); the author of Descartes c’est la France is André Glucksman.

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more recent biographers have enquired whether his philosophydrives his ‘science’ or vice versa, whether they are interdependent,and what role his religious belief plays in his thinking. To somedegree these are questions of emphasis, and mark the perpetual revi-sionism to which all historical thinking is prone; they also reveal thecomplex and many-faceted nature of his work, the interdependenceof its many aspects, and its continued ability to provoke even afterthree and a half centuries.

The Genesis of the Discourse and its Development

Descartes never intended to publish a book like the Discourse; hisplan was to fulfil a promise to his Parisian friends to set down anaccount of his world system, which would be called The Universe. Sothe Discourse and the essays which accompany it are a substitute forsomething else, which would have been more comprehensive, morecoherent, and more ‘scientific’ in character. The essays which followthe Discourse are described by Descartes as no more than ‘examples’of his method in action; in a letter to Mersenne written a few monthsbefore its publication, he claims that the Discourse itself only refers tohis method and its coming into being, and does not state it formallyanywhere in the text: ‘I haven’t been able to understand clearly whatyou object to in the title,’ he writes, ‘for I am not saying Treatise onthe Method but Discourse on the Method, which means Preface orNotice on the Method, to show that I do not intend to teach themethod but only to speak about it’ (AT . ). This was a matter ofdisappointment to his Parisian acquaintances, as Jean-BaptisteMorin pointed out in a letter to him dated February ; itprevented them from engaging in a direct critique of the principlesof Cartesian physics (AT . –).

I have already suggested that one might see the dreams whichDescartes experienced in as decisive in forming in him theambition to discover some new general account of nature; one roadwhich he might have taken to fulfil this was that of assiduous studyof all relevant previous authors. He explicitly discards this as a cor-rect strategy in the Discourse, not only because he had already beeninculcated with what he saw to be unsound ancient philosophy and

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an unsatisfactory world system (the Aristotelian), but also, as hefrequently admits in his writings and his letters, because he foundreading the work of others tiresome. His (not very large) library athis death consisted almost entirely of books that had been given tohim by his friends; to various of his correspondents he expresses hisdislike of ‘fat tomes’, and asks them to recommend short books onsubjects he wishes to study (AT . , ; . ; . –); anearly comment in his unpublished Private Thoughts (Cogitationesprivatae) runs as follows: ‘in the case of most books, once we haveread a few lines and looked at a few of the diagrams, the entiremessage is perfectly obvious. The rest is added only to fill up thepaper’ (AT . ). There is another, more serious, reason to rejectthe accumulation of the views of others as a road to truth. Descartesdoes not quote the popular dictum, ‘Plato is my friend, Socrates ismy friend, but truth is a greater friend’ (to which I shall returnbelow), but he alludes to it. ‘We shall not become philosophers if wehave read all the arguments of Plato and Aristotle, but are unable toform a secure judgement on the matters in hand’, he avers in theRules For the Direction of Our Native Intelligence (AT . ). Heconsistently recommended the ‘light of reason’ as the best guide;but he was later to recognize the power of philosophical name-dropping, for he gloomily confided to Mersenne on September that he had decided in future to back up his argumentswith the authority of others, as ‘truth by itself is so little respected’(AT . ).17

Throughout the s Descartes had been working on geometryand optics, although it seems that the final versions of these works(and the meteorological treatise) were not written until . I havealready mentioned that he was known to be planning an auto-biographical essay entitled ‘the story of my mind’ in ; Guez deBalzac wrote to him on March of that year that ‘it is [eagerly]awaited by all your friends . . . it will be a pleasure . . . to read of thepath you have followed, and the progress which you have made, in[discovering] the truth of things’ (AT . –). It would seem that

17 On these and similar quotations and their currency, see Ian Maclean, Logic, Signsand Nature in the Renaissance: The Case of Learned Medicine (Cambridge, ), –.

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the language of this essay was to be the vernacular; one model forthis, which Descartes certainly perused in spite of his aversion toreading in general, is Galileo’s controversial Dialogue Concerningthe Two Chief World Systems of ; another was the Essays ofMontaigne, a writer certainly known to Descartes, but only namedonce in all his writings (AT . ). Like Descartes, this sixteenth-century author was a legally trained gentleman of leisure, whoengaged in a broad range of reflections (including an assessment ofhis own education) and recorded them in a deliberately informalway; Descartes emulated only Montaigne’s project, and consciouslyrejected his practice of reading widely, excerpting anecdotes andquotations, and musing on his own life and times. Part One of theDiscourse, written during Descartes’s Paris days, may have beenadapted from the account of his intellectual formation to whichGuez de Balzac refers. Whereas in his correspondence on mathemat-ical and optical subjects Descartes was content to write in eitherLatin or French, the decision to incorporate his intellectual auto-biography in the work of may have swayed him to write thewhole text in the vernacular.

The proof of the existence of self and God, which forms PartFour the Discourse, probably dates from the same period or a littlelater. Descartes mentions a treatise on metaphysics to Mersenne in aletter dated April (AT . ); this seems to have accom-panied the composition of the ambitious account of the universeentitled Le Monde, a version of which was begun while Descarteswas still in Paris. Mersenne and others repeatedly urged Descartes tocomplete this work, referred to also as his ‘Physics’, even as late asApril (AT . ). Details about his progress are given invarious letters of the early s. On April Descartes wrote toMersenne:

I can tell you that although the treatise which I promised you at Easter isalmost finished, I would nevertheless prefer to keep hold of it for a fewmonths, as much to revise and polish it as to supply some necessarydiagrams which I am finding a nuisance, for, as you know, I am nodraughtsman, and am very slapdash over things from which I myself canlearn nothing. If you accuse me of having so often failed to keep mypromise to you, my excuse will be that the only thing that has up to now

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made me defer setting down the little I know has been the hope of learningmore and being able to add to the work. For instance, in what I presentlyhave to hand, I did not originally intend, after the general description ofthe stars, the heavens, and the earth, to give an account of particularbodies on the earth, but only to deal with their various qualities. In placeof this, I am now adding something on their substantial forms, and trying toshow the way to discover them all in time by providing experiments andobservations to support my arguments. This is what has taken me awayfrom the work these last days, for I have been engaging in various experi-ments to discover the essential differences between oils, ardent spirits oralcohols, ordinary water and acids, salts, etc. (AT . –)

As the words italicized here by me show (Descartes also sometimesmarks them in this way in letters and texts), Descartes is still relyingon the scholastic vocabulary which elsewhere he decries; this letteralso reveals him, against the popular image of him as a cerebralrationalist, to be habitually engaged in experiments and observa-tions, a feature of his ‘scientific’ practice throughout his life. In June Descartes wrote again to his closest Parisian friend:

I am now here in Deventer; I have decided not to leave here until theDioptrics has been completely finished. For the last month I have beenweighing up whether to give an account of how animals are generated inThe Universe. I have finally decided not to, because it would take me toolong. I have finished all that I intended to put in it about inanimate bodies.It only remains for me to add something about the nature of man. (AT. )

This passage gives us an insight into the confidence Descartes had inhis method; he was willing to contemplate producing his ownaccount of animal generation, apparently without reference to theAristotelian text on the subject, or the more recent work of thePaduan natural philosopher Fabricius ab Aquapendente (–).18 Yet more news about progress was forthcoming in late :

I shall discuss man in The Universe more than I thought, for I am settingout to explain all his main functions. I have already written up the vital

18 See Andrew Cunningham, ‘Fabricius and the “Aristotle Project” in AnatomicalTeaching and Research at Padua’, in The Medical Renaissance of the Sixteenth Century,ed. A. Wear, R. K. French, and Iain M. Lonie (Cambridge, ), –.

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functions, such as the digestion of food, the pulse, the distribution ofnourishment, etc., and the five senses. I am now dissecting the heads ofvarious animals, so that I can explain what imagination, memory, etc.,consist in. I have seen the book De motu cordis [William Harvey’s On themovement of the heart] which you spoke to me about some time ago, and Ifind myself slightly at odds with his opinion, although I only read it afterhaving completed what I had to say on this topic. (AT . )

From these and other letters, we may infer that by the beginning of most of the elements which were to compose The Universe werein draft form: of the Discourse, only Parts Two and Three seem notto have been written out in some form or other. Descartes had madegood progress towards satisfying his friends’ and admirers’ pleas togive a full account of his new philosophy. On July , he wroteagain: ‘My treatise is almost finished. I still have to correct it anddescribe it, but because I don’t need to find out anything new, I havesuch difficulty working on it that if I hadn’t promised you more thanthree years ago to send it to you by the end of this year, I don’tbelieve that I could complete it. But I am very keen to keep mypromise’ (AT . ).

We are able to know what form most of the treatise would havetaken, as a manuscript of Part One (on light) and Part Two (onman) survived among Descartes’s papers (AT . –). The firsttreatise deals first with perception in general, the nature of heatand light emanating from fire, hardness and liquidity, vacuum andimperceptibles, and the number of the elements, before passing onto the description of the new world imagined by Descartes as theparallel to this one. A chapter follows on the laws imposed by Godon nature, which regulate all natural things. Thereafter, accountsare given of the sun, stars, planets, comets, moon, and earth;weight and light are discussed, and tides explained by the move-ment of the earth. The treatise on man describes the human body asa machine, and investigates the movement of the blood, animalspirits, the senses, hunger and thirst, digestion, and the brain and itsfunctions. The account given by Descartes of the work in Part Fiveof the Discourse is therefore quite faithful, although the omission ofthe discussion of tides, which depended on the assumption that theearth moves, is to be noted; this is due to Descartes’s reaction to

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the Galileo affair, which caused a crisis in Catholic Europe in therelations between the Church and the ‘scientific’ community. Toassess the effect of this, we shall have to return to the earlier partof the century, to see how Descartes’s friend and mentor Mersennedealt with an earlier manifestation of this crisis, which arose in, and then show the repercussions of the Galileo affair of in France and Italy.

Galileo, Mersenne, and the Church: Authority and Truth

From the thirteenth century onwards a conflict existed between theRoman Catholic Church (through its bishops, its councils, and itsfaculties of theology) and philosophy. The introduction of Aristo-telianism had highlighted a number of incompatibilities betweenancient and Arabic thought and Christian doctrine, over such issuesas the nature of the soul (whether material or immaterial, mortal orimmortal), the intellect (whether individuated, or shared by allhumanity), and the universe (whether eternal, or created ex nihilo asin the account of the Book of Genesis). This conflict came to expressitself in the opposition of those who rely on written authority (of aninstitution, or a text such as that of Aristotle or the Bible) and thosefavouring free philosophical speculation, who adopted such catch-phrases as, ‘Plato is my friend, Socrates is my friend, but truth is agreater friend’, and the ancient satirist Horace’s declaration that hewas ‘not bound over to swear as any master dictates’ (nullius addictusiurare in verba magistri), which in due course was to become themotto of the Royal Society of London; these dicta, as we shall see,are quoted by Descartes’s friend Mersenne, and are referred to byDescartes himself, in connection with the problems faced by themboth.19

The eminent Italian mathematician, physicist, and astronomerGalileo Galilei (–) was convinced by of the truth ofthe Copernican theory of heliocentrism. In – he constructeda telescope for himself, discovered the four moons of Jupiter (which,

19 See n. , above, and AT . – (letter to Huygens, Oct. ); . (Regulae, ).

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according to traditional cosmology, could not have satellites), andperceived that the Milky Way was a collection of stars and the moonwas not in fact a perfect sphere (as all celestial bodies were supposedto be), but had an uneven surface like the earth; all of these observa-tions flew in the face of Aristotelian and Ptolemaic cosmology, andwere received with great interest throughout Europe, even in Rome,where at the behest of Cardinal Roberto Bellarmino (–),the Jesuit College confirmed Galileo’s findings. Galileo soonattracted to himself a number of enthusiastic supporters, includingthe Neapolitan Carmelite Paolo Foscarini (–), who pub-lished a letter extolling the new cosmology in . But the fact thatthe literal sense of parts of the Old Testament was apparentlyincompatible with Copernican cosmology alarmed the RomanCatholic’s Church’s Inquisitors; they issued a condemnation ofFoscarini’s pamphlet, and formally censored part of Copernicus’book.20

The Inquisition was a medieval institution; it had been recast byPope Paul III in as the Congregation of the Holy Office, andadapted to combat Protestantism, mainly in Italy, although itspowers, wielded by six cardinals, extended to the whole Church.Whereas the medieval Inquisition had focused on popular theo-logical misconceptions which resulted in the disturbance of publicorder, the Holy Office was concerned with orthodoxy of a moreacademic nature, especially as it appeared in the writings of theo-logians. In its first years the activities of the Roman Inquisition wererelatively modest in scope; but Pope Paul IV expanded these, and in ordered the Congregation to draw up a list of books whichcould be deemed to offend faith or morals. This resulted in the firstIndex of Forbidden Books (). By the seventeenth century animpressive number of powerful Counter-Reformation figures hadbeen members of the Roman Inquisition; it is generally agreed thatthey were enlightened and cultured men. For all this, they wereresponsible in Italy for the imprisonment of innovative thinkersof the stature of Giordano Bruno (–) and Tommaso

20 On Galileo, see Stilman Drake, Galileo at Work: His Scientific Biography (Chicago,); Richard S. Westfall, Essays on the Trial of Galileo (Rome, ).

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Campanella (–). Both of these figures published in thevernacular. The Inquisitors were particularly sensitive to books whichwere accessible to the non-learned public; indeed, they ordered theexecution of the former of these heterodox thinkers. They claimeduniversal jurisdiction, but their Index, which underwent constantupdating and revision, was not accepted in France. There, secularlegal assemblies (the parlements) alone had the power of suppressingbooks, although various bodies (including certain religious ordersand the Faculty of Theology of the University of Paris) were able toissue approbations or condemnations of publications. The differencein religious atmosphere between the two Catholic countries is indi-cated by the fact that Campanella was imprisoned for many years inItaly, and on his release was granted refuge and protection in Franceby none other than its chief minister (also a cardinal) Armand duPlessis de Richelieu (–) himself, in the year following theimprisonment of Galileo ().21

The real target of the Inquisitors in censuring Foscarini in was Galileo: he was summoned to Rome to answer to them, andinstructed to express his views discreetly; after this interview theInquisitors issued the following text on March of that year, whichMersenne quotes in full in his long commentary on the early chap-ters of the Book of Genesis (the Quaestiones celeberrimae in Genesim)of :

This Holy Congregation has also learned about the spreading and accept-ance by many of the false Pythagorean doctrine, altogether contrary toHoly Scripture, that the earth moves and the sun is motionless, which isalso taught by Nicolaus Copernicus’ On the Revolutions of the HeavenlySpheres and by Diego de Zuniga’s On Job. This may be seen from a certainletter published by a Carmelite Father, the title of which is Letter of theReverend Father Paolo Antonio Foscarini, on the Pythagorean and Coperni-

21 See Michel-Pierre Lerner, Tommaso Campanella en France au XVIIe siècle (Naples,). Campanella was, it is true, very well treated in Rome, where he performedastrological services for Pope Urban VIII; indeed, this figure organized his transfer toFrance as a way of evading a new and embarrassing request by the authorities in Naples,where he had been held in very harsh conditions for many years, that he be sent back toanswer further charges there. But this fact does not render the general point about thedifference in religious atmosphere in the two countries invalid.

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can Opinion of the Earth’s Motion and Sun’s Rest and on the New Pythago-rean World System . . . In this letter the said Father tries to show that theabove-mentioned doctrine of the sun’s rest at the centre of the world andthe earth’s motion is consonant with the truth and does not contradictHoly Scripture. Therefore, in order that this opinion may not spread anyfurther to the prejudice of Catholic truth, the Congregation has decidedthat the books by Nicolaus Copernicus (On the Revolutions of Spheres) andDiego Zuniga (On Job) be suspended until corrected; but that the bookof the Carmelite Father Paolo Foscarini be completely prohibited andcondemned; and that all other books which teach the same be likewiseprohibited . . .22

Mersenne held strong views both about the authority of thisjudgement and the relation of ‘scientific’ truth to Catholic doctrine.These he expressed in his commentary on Genesis. In its Preface herepudiates the view that Catholic doctors and theologians followonly Aristotle and ‘swear by his words’, referring to one of the dictaquoted above; referring to the other, he claims that truth is mostfriendly to Catholics of all thinkers, for they are able to readjust theirbeliefs in the light of experience and observation. He acknowledgesthat there is a problem in how difficult passages of Holy Writ are tobe interpreted (for example, chapter of the Book of Joshua, inwhich the sun is said to stand still in the sky: this is the passage onwhich Galileo writes the most); he refers here to the principle ofaccommodation invoked by St Augustine, according to which theliteral sense of Scripture can be set aside, if it can be shown that thepurpose of the text is to accommodate itself to common humanexperience (for example, that the sun rises and sets, and movesacross the sky). Mersenne claimed that as no definitive theologicalstatement about the meaning of passages which support this way ofperceiving the movement of the heavens had been issued by theChurch, the matter was still to be resolved.23

Later in the same work he returned to the issue of error andheresy, in an article entitled ‘whether anyone is able, without at least

22 Quaestiones celeberrimae in Genesim (Paris, ), col. .23 Galileo interpreted Joshua in the letter to Grand Duchess Christina of Tuscany,

of : see Galileo, Opere, ed. Antonio Favaro (Florence, –), . –;Mersenne, Quaestiones in Genesim, preface.

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a mark of heresy or error, or without danger of temerity, to hold anddefend the opinion that the earth moves and the heavens areimmobile’; it is pertinent to quote at length what he says, because itprefigures very closely the line that Descartes himself was going totake:

First, it must be laid down that heresy is nothing other than pertinaciouserror in faith, which is located in a refusal to believe what it is agreed thatthe Church has put forward to be believed . . . I designate as heretics thosewho pertinaciously, and by an act of the will after due reflection, call intoquestion things which the Church puts forward to be believed even if theydo not expressly dissent from them . . . An opinion is called erroneous, ifit denies something which, although not itself a matter of faith, neverthe-less is able to be deduced as an incontrovertible consequence of a matter offaith: as for example that Christ was capable of laughter, because he wasa man, and so forth . . . An opinion should be deemed temerarious, ifwithout any reason it is affirmed contrary to the unanimous consensus ofthe doctors.

With these points established, it is easy to reach the judgement that theview which attributes motion to the earth and denies it to the heavens isnot heretical; nor is it an error in faith, since the Church has not yet putanything on this issue forward to be believed . . . In fact, the Church didnot decree that all the details in Holy Writ are to be believed to the pointthat we instantly ought to give credence to them in the way that they seemto have meaning for us; for the meaning in which we believe is thatintended by the Holy Spirit and declared by the Church, else our faithwould be contrary to itself, and would change wherever it attributes onesense to one place and a different one to another. But those places ofScripture which deny the motion of the earth or attribute it to the heavensor the stars have not as yet been declared or expounded by the Church insuch a way that we ought to believe them in their literal sense, and thatthey should be understood in a way they literally sound . . . we ought firstto listen to the Church, and from her learn whether anything should betaken in its proper sense or metaphorically . . . there are a thousand otherplaces in Scripture, which are not to be expounded according to the literalsense . . . God has willed that Holy Writ accommodates itself to ourunderstanding and senses, especially in those things, which have to dowith nature and with things visible. This is clear from the bodily membersattributed to God, such as feet, shoulders, ears, eyes, a thigh, and wings.And I do not see why we should not be able to determine whether those

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places of Scripture which affirm that the earth stands still, where the issuehas not been settled by the Church, are to be understood literally . . . thereis nothing preventing the passage in which Joshua ordered the sun tostand still upon Gibeon and the moon in the valley of Ajalon being ableto accommodate itself to our senses, which deem the stars and theplanets to go around daily in their whole course, from rising to setting,since nothing is present which could correct the senses by reason, andestablish that the same thing is happening as with those human beingswho, when they are being transported on a ship, trust in their sensesalone, and believe themselves to be standing still and the harbour to beapproaching or receding, or the banks of the river to be moving by. Iseem to remember that St Augustine follows the literal sense in interpret-ing Holy Writ whenever no problem arises with another place in Scrip-ture, or with a decree of the Church, or with reason. But in truth, thosewho want the earth to be endowed with motion, and on the basis of reasonwant to deny that it is at rest, if they are Catholics, will be prepared toobey a decree or determination of the Church on this issue, and as hertrue sons and faithful members, to submit themselves altogether toher.24

This is a somewhat tortuous passage, revealing not only embarrass-ment, but also an implicit suggestion that the Inquisition’s judge-ment was not of sufficient weight to decide the issue in question;Mersenne’s references to the Church imply a conciliarist position,which sees the Church in Council as the only legitimate body todetermine a point of doctrine. This suggestion would seem to createa space in which pious Catholics could work without showing dis-obedience to the Church, provided that they were discreet. Such aposition was, however, compromised by the events which followedthe publication of Galileo’s Dialogue in . Galileo may well havefelt secure in publishing this pro-Copernican work for variousreasons, not least that his patron, Matteo Barberini (–),who in had indicated that he was sympathetic to Galileo’sastronomical views, had just been elected pope as Urban VIII. Butthe book caused a furore, and its sale was suspended six months afterits publication. Galileo was summoned to Rome, where Urban VIII(possibly angered by what he took to be a personal slight in the

24 Mersenne, Quaestiones in Genesim, ix. , cols. –.

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Dialogue) decided in June that Galileo should be imprisoned forlife.25

In November , Descartes wrote the following to Mersenne:

I had indeed intended to send you The Universe as a New Year gift, andonly two weeks ago I was still quite determined to send you at least a partof it, if the whole work could not be copied in time. But I must confessthat I recently made enquiries in Leiden and Amsterdam as to whetherGalileo’s World System was not already there, because I seem to rememberhearing that it has been published in Italy last year. I was told that it hadindeed been published but that all the copies had immediately been burntat Rome, and that Galileo had been convicted and punished. I was soshocked by this that I almost decided to burn all my papers or at least tolet no one see them. For I could not imagine that an Italian such asGalileo, who was also, as I understand it, well looked on by the pope, couldhave been made a criminal for any other reason than that he tried, as he nodoubt did, to establish that the earth moves. I know that some cardinalshad censured this view some time ago, but I thought I had heard it saidthat it was being taught publicly even in Rome. I must admit that if theview is false, so too are the entire foundations of my philosophy, for it canbe demonstrated from them quite clearly. And it is so closely allied toevery part of my treatise that I could not take it away without making thewhole work defective. And as I would not for all the world want any workof mine to contain a single word that could be disapproved of by theChurch, I have preferred to suppress it rather than to make it available in amutilated form. I have never felt any inclination to produce books, andwould never have completed this one if I had not been bound by a promiseto you and some other of my friends; it was thus my desire to keep myword to you that constrained me all the more to work on it . . . There arealready so many views in philosophy which are no more than plausible andwhich can be maintained in debate that if my views have no greatercertainty than that and cannot be approved of without controversy, Irefuse ever to publish them. Yet, I would look ungracious if, having prom-ised you the work for so long, I tried to fob you off with a flippant reply ofthis sort; so, after all, I shall not fail to let you see as soon as I can what Ihave composed, but I ask you kindly to allow me another year to revise andpolish it. . . . I ask you also to tell me what you know about the Galileoaffair . . . (AT . –)

25 See William Shea, Galileo in Rome (Oxford, ).

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Descartes was further perturbed by an official Catholic documentissued in nearby Liège in September , which he reproducesverbatim in a letter to Mersenne:

The said Galileo, therefore, who had confessed at an earlier interrogation,was summoned to the Sacred Tribunal of the Inquisition, interrogated,and detained in prison. As he had done on a previous occasion, he clearlyshowed himself to be of the same opinion, though he pretended thathe put forward his view only hypothetically. The outcome is that afterdiscussing the matter thoroughly, the Most Eminent Cardinals of theCommissionary General of the Inquisition have pronounced and declaredthat the said Galileo is under strong suspicion of heresy, in so far as hehas followed a doctrine which is false and contrary to Holy and DivineScripture, namely that the sun is the centre of the universe and does notrise or set, and that the earth moves on the other hand, and is not thecentre of the universe, insofar as he has been of the opinion that thisdoctrine could be defended as worthy of belief, even though it has beendeclared contrary to Holy Scripture. (AT . )

The reference to Galileo’s unsuccessful line of defence––that he wastreating Copernicanism not as a true doctrine but a convenienthypothesis for the computation of celestial events––alarmed Des-cartes most: this had been, since the first publication of the Derevolutionibus in , the favoured line taken by a number of Cath-olic and Protestant astronomers to defend their use of Copernicantheory, and would have suited his own purposes very well. His nextsurviving comment is found in a letter to Mersenne of February, and reiterates the view expressed by his Parisian friend in hiscommentary on Genesis:

The knowledge that I have of your virtuous nature makes me hope thatyou will think even better of me when you see that I have decided whollyto suppress the treatise I had produced, thereby losing almost all of mywork of the last four years in order to give my complete obedience to theChurch, since it has condemned the view that the earth moves. Yet, all thesame, as I have noted that the condemnation has not yet been ratified bythe pope or the Council (it was made by the Congregation of Cardinals setup to censor books), I should be grateful to know what the view on thismatter is in France and whether their authority has been sufficient tomake the condemnation an article of faith. I have come to the view that the

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Jesuits have helped to get Galileo condemned: Father Scheiner’s entirebook clearly shows that they are no friends of his. Besides, the observa-tions in the book provide so many proofs which remove from the sun themotion attributed to it that I cannot believe that Father Scheiner is nothimself privately persuaded of the Copernican position; a thought I findso shocking that I dare not write down my feelings on the matter. (AT. –)

The Jesuit Father Christoph Scheiner (–) of Innsbruckhad published a book entitled Rosa Ursina between and ,which agreed with Galileo’s claims about sunspots but attackedheliocentrism; Descartes seems here most shocked by his supposedhypocrisy, although there is nothing in this or any subsequent writ-ings by Scheiner to suggest he was anything other than sincere in hiscosmological beliefs.

It would seem that, up to this point, Descartes’s communicationswith Mersenne were not intended for public consumption; that doesnot seem to be the case with the letter of April , which beginswith a strangely formal (and indeed otiose) opening statement (it ishighly likely, in spite of the mysterious non-arrival of part of theircorrespondence (AT . ), that Mersenne knew about the Galileoaffair, and knew also that Descartes knew of it), and repeats pointsthat already had been made in their correspondence: this indicates, Ibelieve, that Descartes wanted the letter to be circulated in theappropriate quarters in Paris as a quasi-public declaration of hisposition (a practice he refers to in an earlier letter to Mersenne: AT. ):

I am sure that you know that Galileo was recently reprimanded by theInquisitors of the Faith, and that his views about the movement of theearth were condemned as heretical. Now I must confess to you that allthe things I set out to explain in my treatise, which included the doctrineof the movement of the earth, were so interdependent that it is enough todiscover that one of them is false to know that all the arguments I wasusing are unsound. Though I was of the opinion that they were supportedby very certain and uncontrovertible proofs, I would not wish, for any-thing in the world, to maintain them against the authority of the Church. Iknow that it might be said that not all the decisions of the Roman Inquisi-tors become immediately articles of faith, but must first be considered by

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a Council of the Church. But I am not so fond of my own ideas as to wantto use such legalistic arguments as a way of clinging on to them . . . Idesire to live in peace and to continue the life I have begun under themotto ‘he who remains well hidden lives well’ . . .

As for what you tell me of Galileo’s experiments and observations, Ideny them all; but I do not conclude the motion of the earth to be any lessworthy of credence . . . (AT . –)

The similarity to the attitudes expressed by Mersenne in quoted above is striking. Descartes then refers to the work of apriest, just possibly Mersenne himself, but more plausibly IsmaëlBoulliau (–), who had indicated that he wanted to use Des-cartes’s physical explanations of the heavens, and whose cosmologywas Copernican:

I am astonished that a man of the Church should dare to write about themotion of the earth, whatever excuses he may give for doing so. For I havean official document about Galileo’s condemnation, printed at Liège on September , which contained the words, ‘though he pretended thathe was putting forward his view only hypothetically’; they seem thereby toforbid even the use of this hypothesis in astronomy. This prevents mefrom venturing to let him know any of my thoughts on the topic. More-over, I do not see that this censure has been endorsed by the pope or aCouncil of the Church, but only by a specific congregation of the car-dinals of the Inquisition: so I do not altogether abandon the hope that thesame may happen as with the Antipodes, which were similarly condemnedlong ago. So in the fullness of time my Universe may yet see the light ofday; in which case I shall myself need to employ my own arguments . . .(AT . –)26

The reference to the Antipodes, the existence of which had beendenied in an eighth-century Church Council, is found also inMersenne, and was a convenient way of reminding the RomanChurch that doctrines it adopted or condemned had varied overtime. It is somewhat puzzling that Descartes should have reacted sostrongly in this open letter to the Roman condemnation of a doctrinethat had not been condemned in Paris; from his retreat in the

26 The suggestion of Boulliau is made by Adam and Tannery; Robert Lenoble,Mersenne ou la naissance du méchanisme (Paris, ), , suggests that Mersenne is herereferred to.

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Netherlands he had absolutely nothing to fear from the Inquisitionitself, and would have had nothing to fear in the French capitaleither. One part of the explanation might be that he hoped––a hopehe expressed in later correspondence––that his philosophical systemwould be adopted by Jesuit schools in France, and saw it necessary toset down where he stood on the matter of Copernicanism, as elem-ents of it were presupposed in his new physics. The private andfastidious Descartes may also have shuddered at the thought of beingexposed to public shame by being associated with the Parisian free-thinkers of the s, whose alleged atheism he had set out to refute.What emerges from this letter is the claim that Descartes’s system isnot a hypothesis (this had been outlawed by the Liège letter); it is infact, as we shall see, the hypothesis of a hypothesis: he has recourseto the fiction that he is describing not the world as it is, nor thephenomena of the world as they can be explained by a mental con-struction such as heliocentrism, but a fictional history of the coming-into-being of a world which is parallel to this one, but is not this one.His extreme sensitivity to the Galileo condemnation may in part beexplained, therefore, in the light of his aspiration to have his worldsystem supplant that of Aristotle in Jesuit and other schools inFrance.

On August we have the first record of Descartes’s directencounter with Galileo’s book:

Mijnheer Beeckman came here on Saturday evening and lent me the bookby Galileo. But he took it away with him to Dordrecht this morning, so Ihave only had it in my hands for thirty hours. I took the opportunity ofleafing through the whole book; and I find that he philosophizes very wellon motion, though there is very little he has to say about it that I findcompletely true . . . In The Universe I had also explained [the ebb and flowof the tide] in terms of the motion of the earth, but in a quite different wayto his . . . (AT . –)

At some point in Mersenne himself chose publicly to commenton the Galileo affair in two vernacular texts, one entitled New Ques-tions (Questions inouyes), the other Theological, Physical, Ethical, andMathematical Questions (Les Questions théologiques, physiques, moraleset mathématiques); he may have been prompted to do this because

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Galileo was being discussed in such popular Parisian institutions asthe ‘Bureau d’Adresse’, a forum for open debate run for the delect-ation of curious and non-specialist audiences by ThéophrasteRenaudot (–). This Protestant publicist enjoyed the protec-tion of none other than Richelieu himself, who seems to have seen itto be in France’s interest to foster a degree of open debate as a way ofmarking his nation’s distance from the papacy. The motion of theearth had been discussed in in the Bureau d’Adresse; Renau-dot, who was also responsible for a weekly news organ (the Gazette)duly reported Galileo’s condemnation in it, and translated its text infull; but in a gesture consistent with the ecclesiastically independentpolicy of his patron, he went on in to print the previous year’sdebates about the motion of the earth. For his part, Mersenne pub-lished in his Theological Questions another, more accurate, Frenchtranslation of the whole text of the condemnation, and of Galileo’sabjuration; he also returned to the issue of the authority of the textof the Bible and of the Inquisition. After setting out the variouspositions dispassionately, but not putting up counter-arguments toall of Galileo’s points, he recommends obedience to the Church, butdiscreetly suggests at the same time that the issue has not yet beendefinitively settled by a formal decision of the Church in Council. Inhis own accounts of the arguments for and against the earth’smotion, it is not difficult to sense his strong sympathy for theCopernican position. He was advised that this did not show suf-ficient submission to the Church, and reissued the Questions with amore acceptable text; however, he circulated the first version totrusted correspondents, and ended his consideration with a refer-ence to the Pauline verse about human ignorance (which might wellrefer also to ecclesiastical blindness too): ‘for now we see through aglass, darkly: but then face to face.’27

Descartes, meanwhile, continued to tinker with his manuscript.

27 Mersenne, Questions inouyes (Paris, ), q. ; Les Questions théologiques,physiques, morales et mathématiques, ed. André Pessel (Paris, ), qq. , , , (both versions); Howard M. Solomon, Public Welfare, Science and Propaganda inSeventeenth-Century France: The Innovations of Théophraste Renaudot (Princeton, );Premiere centurie des questions traitees ez conferences du Bureau d’Adresse (Paris, ),–; Cor. : . See also Lenoble, Mersenne, –.

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The Galileo affair had caused him to suppress the publication in fullof his treatises, but he was able (in Part Five of the Discourse) to givequite a full résumé of their contents, omitting only any reference tothat which would commit him to the view that the earth moved (thechapter on tides––the same caution can be seen to influence PartThree of his Principles of Philosophy, published ten years later). Des-cartes wrote to Mersenne in the late summer of that he hadrevised and completed the Dioptrics; on November of that year hewrote to Huygens about his plan to publish this treatise as well as theMeteorology with a ‘preface’ (AT . –), and he responded inFebruary to Mersenne’s suggestion that the Discourse shouldprecede the three treatises, which he eventually adopted. By thattime the process of its production had already begun.

The Publication of the Discourse

We have seen that the volume published in June is an amalgamof various different works, composed over a long period. The idea ofa work on geometry (including optics) dates from Descartes’s inter-action with Beeckman; the first version of Part One of the Discoursedates back to Descartes’s Paris days; Part Four was in draft around; the Dioptrics was ready in October , a month or so beforethe Meteorology. The final version of the Geometry was composedduring the printing of the Meteorology. The composite work (onwhich Descartes worked hard to confer a sense of unity) was origin-ally to be called ‘The Project of a Universal Science Which CanBring Our Nature To the Highest Degree of Perfection. With Diop-tics, Meteorology, and Geometry, in Which the Most CuriousMatters Which the Author Could Have Chosen To Establish theUniversal Science He Is Proposing Are Explained in Such a WayThat Even the Unlearned Will Be Able To Understand Them’(AT . ); this was abandoned for the eventual title some time in, probably after consultation with Mersenne.28

Descartes moved to Leiden in March of that year; he confided inMersenne that the most prominent of all Dutch publishing houses,

28 For the dates of composition, see Gaukroger, Descartes, –.

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the Elzeviers, were rather grandly expecting him to pay court tothem (something that his aristocratic nature made him loath to do),so he had decided to look elsewhere for a printer. He consideredsending his manuscript to Paris, but doubted whether his handwrit-ing was legible enough or his diagrams well enough drawn to bereliable copy for submission to a compositor; he was also keen ona contract which would give him copies for distribution (AT. ). He entered into an agreement with the Leiden printer-publisher Jean Le Maire (or Maire) on December , whichrestricted Le Maire to producing two editions totalling no more than, copies, and gave Descartes the number of presentation copieshe desired. This was a hard bargain, for authors did not usuallyreceive as many copies for distribution to their friends and patrons; Ido not think, however, that Descartes was impelled by meanness inthis case (although there is a certain amount of circumstantial evi-dence that he was very careful with his money). He had, after all,offered to put up the money to guarantee the publication of a Life ofSaint Elizabeth in October , which Mersenne was keen onhaving printed in Holland (AT . ). His manner of negotiatingmay well have something to do with his status as a gentleman. Bydistributing the copies to his colleagues and friends, he was engagingin an aristocratic culture of gift-giving, an important practice ofthe society to which he belonged and in which he moved. He wasalso rather loftily disowning an interest in the fate of the rest ofthe edition; even though he clearly hoped that a broad public wouldread his work, his personal intention was to communicate his viewsto the chosen few from among the number of his fellow-scholars andthe court. Evidence of this attitude recurs when, in , he dis-cussed with Mersenne the arrangements for publishing the Medita-tions. He had originally only planned to have an initial print-run ofabout twenty to thirty copies of this work, which he proposed tofinance himself, for him to send to the ‘most learned among thetheologians’ (AT . ); it was only when he realized that it would,willy-nilly, be more widely circulated (as recipients would lend theircopies to other readers) that he relented, and changed his view (AT. ).

Jean Le Maire (?–) was a member of the liberal

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(remonstrant) wing of the Calvinist Walloon Church; he may nothave been as prominent as the Elzeviers, but he was an enlightened,shrewd, enterprising, and long-established publisher. He had takenover the family business in , and his portfolio of authors eventu-ally included a number of important contemporary Dutch andFlemish humanists, including Daniel Heinsius (–), JustusLipsius (–), and Gerard Vossius (–), as well as thegreat Erasmus (–). He also had strong connections withFrench expatriate scholars such as Claude de Saumaise and AndréRivet (–); he even published works by Descartes’s Parisianacquaintances Guez de Balzac and Gabriel Naudé. The period oftime the Discourse took to print––more than five months––suggeststhat Descartes was an exacting author. He certainly had very specificrequests, including the production of a number of large-paper cop-ies of the Geometry to allow their owners to write copious notes inthe margins; he claims in a note he appended to the Discourse that hehad to deal with non-Francophone compositors, which may havecompounded the difficulties he experienced in the printing house,but provided him with an excuse for the errors to be found in thetext.29

There were other problems that emerged along the way, not leastthat of the ‘privilege’, or licence to print. This was effective only in agiven jurisdiction: Descartes wanted one to be obtained for his workin both France and the Netherlands to protect it against piracy. Itseems that his friend Huygens obtained for him the Dutch privilege;Mersenne was entrusted with the task of securing the French one,which he did with characteristic zeal: indeed, too much zeal for thetaste of the fastidious Descartes. Royal privileges were expensivethings; in order, probably, to ensure that Descartes would have noth-ing to pay, Mersenne made supplication to the Crown on his behalf

29 Gustave Cohen, Ecrivains français en Hollande dans la première moitié du XVIIe

siècle (The Hague and Paris, ) (pp. – for the Descartes privilege); AT . , (letter to Mersenne of Nov. about the publication of the Meditations, whoseprinter also contracted to give a very large number of free copies to Descartes; this letteralso reveals Descartes’s misconceptions, about the economics of publishing); RonaldBreugelmans, Fac et spera: Joannes Maire, Publisher, Printer and Bookseller in Leiden– (Houten, ).

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in appropriately hyperbolical terms. These were enshrined (as wasthen the practice) in the preamble to the document, which wassigned in the king’s name on May :

Given that discovery in the sciences and the arts, accompanied by dem-onstrations and applications, is a product of superior minds, this hascaused princes and states to receive inventors with every sort of gratifica-tion, so that their states might become more flourishing as a result oftheir discoveries. So it is that our well-beloved Descartes made it knownto us that by long study he has come across and demonstrated manyuseful and beautiful things previously unknown in the human sciences,which touch on various arts and the ways of applying them . . . (AT. )

The text continues in the normal way, setting out the names of theworks protected by the licence and the legal penalties incurred if it isinfringed; even here there are signs of royal favour, for the privilegegenerously covered all present and future works by Descartes for tenyears, and gave him a much better share of any fines levied: whereasnormally the Crown took a third share, this is forgone, leaving onlytwo joint beneficiaries, namely, the poor and the author. ButDescartes was furious. He was named in the document, whereas hehad studiously kept his name off the title-page; this offended hissensitive aristocratic and private nature as much as did the dithy-rambic compliments. He allowed only an extract of the privilege tobe printed in the Discourse (the full text appeared, however, insubsequent publications), and protested to Mersenne, who wasunderstandably hurt after all his efforts to save Descartes money andenhance his prestige; Descartes was later to apologize for hisungenerous reaction.30

There is evidence that much, if not all, of the Discourse and theaccompanying treatises were circulated before publication, in somecases in the form of page proofs. Jean de Beaugrand, an agent for theChancery in Paris whom Descartes regarded as an enemy, asked oneof his correspondents in Leiden to send him sheets as they came offthe presses, and managed to obtain a copy of the work before even

30 Baillet, Vie, . .

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Descartes’s friends; he it was who forwarded it to the mathematicianPierre de Fermat, another of Descartes’s adversaries, probably tostimulate a critical reaction to the work. In the end, it seems that onlyone edition of copies was printed, including the which Des-cartes received for distribution to his friends; and even these did notsell well. On receiving some corrections to the text from the ever-attentive Mersenne, Descartes wrote on January that he hadgone to this trouble for no purpose: ‘in view of the few copies thebookseller says he has sold,’ he wrote, ‘I see no great likelihood of hishaving to print it again’ (AT . ). The same fate awaited theElzevier edition of the Meditations of . According to one source,Le Maire’s edition was not even sold out at the time of Descartes’sdeath; but the Latin version, which appeared with Descartes’s bless-ing in , was eagerly purchased by the scholarly communitythroughout Europe, and was a commercial success. Le Maire himselfwas to publish the Geometry in Latin in , which may well havegiven him a better return on his investment than did the Discourse.This reveals that the choice of the vernacular restricted the dis-semination of the first publication of the Discourse; but it may alsobe that it reflects Descartes’s own narrow expectations about itscirculation.31

The Discourse

As has already been intimated, and will become even clearer below,Descartes did not envisage a single readership for his book; it wasexplicitly aimed at both his ‘scientific’ and philosophical colleagues,and a broader constituency of more or less well-educated men andwomen with an interest in the intellectual life of their day. Thesewould have included members of the professional classes, legal andcourt officials, surgeons, merchants, and (increasingly) their wivesand daughters, together with other literate persons having access tovernacular publications. These readers were served by institutionssuch as the Bureau d’Adresse, and by popularizing ‘scientific’ works

31 Gaukroger, Descartes, –, –; F. E. Sutcliffe, Descartes: Discourse on Methodand the Meditations (Harmondsworth, ), ‘Introduction’, p.

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such as Mersenne’s New Questions of and Charles Sorel’s(?–) The Knowledge of Material Things (La Science des chosescorporelles), which appeared in the same year. The famous openingremark of the Discourse about ‘good sense’ and its equal distributionstrongly suggests that what he is going to say will be accessible to all;but the introduction to the essay entitled Geometry makes the dualnature of his readership explicit: ‘Up to this point I have tried tomake myself understood to everyone; but, with regard to this trea-tise, I am afraid that it cannot be read except by those who alreadyknow what is to be found in the books of geometry; for, given thatthey contain so many well-proven truths, and thinking that it wouldbe superfluous to repeat them, I have not failed to make use of them’(AT . ). It might be concluded from this, and from his claim atthe very beginning of the Discourse that ‘the power of judging cor-rectly and of distinguishing the true from the false is naturally equalin all men’, that Descartes imagined that everyone might attain to allknowledge, given the proper training, but that is clearly not the case,as his comment in Part Five reveals: ‘as much inequality is foundamong animals of the same species as among men, and some areeasier to train than others’ (AT . ); his scathing assessments of hisfellow mathematicians seem also to be based on their (alleged)inequality of intellect to his own.

Part Six: The Presentation of the ProjectThe Discourse is somewhat unusual for its day, in that it does notopen with a dedicatory letter to a prominent figure, and has noformal preface addressed to the reader to prepare him for what isto come. In so far as such prefatory material is present in thework, it is to be found in the last part of the Discourse, called byDescartes its ‘description’ in the letter of July , quoted above.It is appropriate to consider this first, as it is here that he intro-duces the work in the traditional way known as the ‘access to theauthor’ (accessus ad auctorem). This included the moral presenta-tion of a writer (in Descartes’s case, it is self-presentation), givinghis name (or in Descartes’s case, suppressing it), the work’s title,the motive for its publication, the ordering of its material, thedignity and utility of its subject-matter, and the genre to which it

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belongs. Normally this would be done by a lecturer presenting thework of another writer; but there are precedents of self-presentation from the ancient world which were known to hiscontemporaries: one of these was afforded by the ancient Greekmedical writer Galen, whose account of his own work is made upof a very un-Cartesian mixture of argument, polemic, anecdote,autobiography, and digression. Some Renaissance authors alsoproduced works at the end of their lives which offered such anintroduction. The famous Dutch humanist Erasmus was one ofthese; another was Girolamo Cardano (–), who is closer tobeing a model for Descartes, in that his name was not alreadywidely known when he produced the first version of the De librispropriis, a treatise on his own writings, and who, like Descartes,sought to write a radical new account of the whole of philosophy;but there is no indication that Descartes ever read much of hiswork attentively32 (although he had almost certainly heard of him,if only through Gabriel Naudé, who in the turbulent Paris of thes was his defender against charges of magic, and eventually theeditor of his autobiography). Cardano was more notorious thanfamous, having been attacked as a libertine writer by the intem-perate Jesuit François Garasse (–) in his anti-libertineCurious Doctrine of the Wits (or Supposed To Be Such) of Our Time,published in . Interestingly, Cardano relates a number of hisdreams in On My Own Books, one of which he looked on asparticularly prophetic, as it helped form his sense of destiny as awriter; we may contrast this with Descartes’s studious silence onthe same matter.33

Descartes’s intellectual autobiography (Part One of the Discourse),which I shall consider below, had already sketched out how hearrived at his general project; Part Six concerns the narrower ques-tion of the motivation which first led him to abandon the idea of

32 But see Geometry, AT . –, where a passage from Cardano’s Ars magna of (a mathematical work) is discussed. I am grateful to Noel Malcolm for pointing this outto me.

33 On accessus, see Ian Maclean, Cardano: De libris propriis (Milan, ), ‘Introduc-tion’, pp. –, –; on Cardano, see Gabriel Naudé, Apologie pour tous les grandspersonnages qui ont esté faussement soupçonnez de magie (Paris, ).

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publishing, and then to make him change his mind. Convention-ally enough, Descartes claims that it is everyone’s duty to benefittheir fellow men if they can; he aspires to offer an example ofreaching the truth through the secure grounding of principles, andthe careful checking of further conclusions by engaging in obser-vations and experiments which settle which of various possiblealternative interpretations is to be preferred. His answer to thequestion of which branch of learning he is setting out to serve isambitious: he suggests that his work will contribute to metaphys-ics, mathematics, mechanics, and physics. He is looking to securepractical benefits for his fellow man (not least in the field ofoptical-instrument making); and eventually he hopes that all thiswill allow him to make progress in medicine, as the restoration andmaintenance of health and the prevention of the effects of ageingseem to him to have a place among the highest goods of life. He issevere in his judgement of ill-considered collaboration, which hebelieves will lead to time-wasting; and he is horrified at the pro-spect that his ideas will be taken up by thinkers who do not pro-ceed with his mental rigour and discipline, but will claim to beworking with him. Earlier in the Discourse he had poured scorn on‘those who, believing themselves cleverer than they are, cannotstop themselves jumping to conclusions, and do not have enoughpatience to govern their thoughts in an orderly way, with the resultthat once they have allowed themselves to doubt accepted prin-ciples and stray from the common path, they would never be ableto keep to the road that one must take to proceed in the rightdirection, and would remain lost all their lives’ (AT . ). Thisprovides him with another motive for publication: that of wishingto eliminate, or at least reduce, the risk of misrepresentation, atthe same time as setting out his own achievements. His finalremarks are devoted to justifying his choice of French rather thanLatin: he believes that this will send out a signal that he is inter-ested only in the expression of pure reason, and wishes to showthis by making no allegation of the authority of others, and byeschewing the use of the language of his teachers and of the inter-national community of natural philosophers. This last decisioncertainly brought him a new class of reader in France; but it did

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not give him the desired exposure to his ‘scientific’ colleagues, andled him to revert to writing in Latin, and to agree to the transla-tion of the Discourse a few years later. His preoccupation withlanguage (shared with some of his contemporaries, including theauthor of the prospectus on a new linguistic project he discusseswith Mersenne in a letter dated November : AT . –)may be linked to his development of a new and more elegantmathematical notation, which is one of the achievements of theessays which accompany the Discourse.

Parts One and Two: Intellectual AutobiographyI quoted above from the letter in which Guez de Balzac urgedDescartes to set down the ‘story of his mind’. Descartes and hiscontemporaries would have been aware of the existence of suchaccounts, from Augustine’s Confessions to Montaigne’s chapter onhis own education in the Essays (. ). Descartes’s approach toautobiography is innovative in various respects. He does not relatehis progress to his temperament, although in letters he talks abouthis weakly physical disposition as a child and the bellicose humourhe attributed to himself in his early manhood (AT . –; . ).This is very much an intellectual autobiography; it refers in passingto the staunchness of his religious faith, but mainly concerns hismind. If we recall that in the Meditations he defined thinking in abroad way––doubting, understanding, affirming, denying, willing,not willing, imagining, having sensory perceptions (AT . )––wecan understand why he chose to portray his development by includ-ing in it a broad account of his mental life. He calls it a story orfable, and later disclaims any intention of inculcating precepts forliving; in this he resembles Montaigne, who also insists that he isnot teaching, but telling a story, and is doing so principally forhimself. But he also suggests, as does Montaigne, that everyoneshould engage in a similar process, and that others might at leastlearn from this narrative of his life what ought to be avoided. Headmits that he hopes to learn from the public’s reaction to hisaccount, just as the ancient Greek painter Apelles had learnt whatothers made of his paintings by hiding behind them and eavesdrop-ping on their comments (AT . ). He insists further that he is

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speaking without the benefit of the divine inspiration which theo-logians possess: here we may suspect him of coyness about his ownvocation.34

His account of traditional philosophy is scathing: it is a training inhow to impress others, and disguise one’s own ignorance; what maymost usefully be learned from it is the ability not to be fooled by itsclaims. As we would expect from someone who found all previousphilosophy and ‘science’ to be unsatisfactory, and who gives such anegative account of his own education, he declares that what he haslearned comes not from the books of the ancients, but from the greatbook of the world. This has taught him to see his upbringing and thevalues implicit in the judgements he passes on others in relativeterms, but does not cause him to relativize his own religious beliefs.Such a rejection of one’s education might be seen as a necessarygesture, arising from the very nature of an intellectual auto-biography; but the insult to philosophy goes beyond this, and castsan odd light on the letter he wrote to one of his Jesuit teachers(possibly Father Étienne Noël) at the Collège de la Flèche on June, to accompany a presentation copy of the Discourse (AT . –). In it he thanks the addressee for inculcating in him the first seedsof philosophy and letters, offers him his book as a tribute to his timeat La Flèche, and invites him to communicate any corrections to itsauthor, in apparent blithe unawareness that the account he gives ofhis philosophical training at that very establishment might be foundoffensive.

Parts Two and Three: Precepts in Philosophy and EthicsThe Discourse is not about all method, but the method required forthe ‘scientific’ investigation of nature. Descartes knew of somepast attempts to find a universal method: he mentions that of themedieval theologian Raymond Llull (–?), which he clearlydeems to be a failure, and refers to another attempt––possibly thatof the sixteenth-century French philosopher Pierre de la Ramée(–)––with a little more respect; but he does not mention othermore recent projects which set out to avoid the allegedly cumbrous

34 Montaigne, Essais, ., pp. –: also n. , above.

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baggage of Aristotelian thought, including that of Francis Bacon.Although he clearly has himself devised a method, he claims not togive an account it; instead, he offers two sets of precepts which heuses as ways of dealing with the error which may exist in his ownmind, of building the foundations he needs to make progress in hisown work, and of dealing with everyday moral problems as thesearise, knowing that for the time being anything certain in such adiscipline was unobtainable. The first set concerned the preliminarydiscipline to which he subjected his mental habits. He resolved‘never to accept anything as true that I did not incontrovertibly knowto be so; that is to say, carefully to avoid both prejudice and prematureconclusions; and to include nothing in my judgements other thanthat which presented itself to my mind so clearly and distinctly, that Iwould have no occasion to doubt it’; second, ‘to divide all the dif-ficulties under examination into as many parts as possible, and asmany as were required to solve them in the best way’; third, ‘toconduct my thoughts in a given order, beginning with the simplestand most easily understood objects, and gradually ascending, as itwere step by step, to the knowledge of the most complex; and positingan order even on those which do not have a natural order of prece-dence’; fourth, ‘to undertake such complete enumerations and suchgeneral surveys that I would be sure to have left nothing out’ (AT. ).

His contemporaries would have recognized some of the pro-cedures of traditional philosophy here; division and definition, forexample, are processes whereby analysis of an object is undertaken;and exhaustive enumeration of a field of enquiry is itself not a novelprecept, being one of the the three laws of predication (kata pantos:see Aristotle, Posterior Analytics, i., a ff.); but the categoriesincontrovertible, prejudice, clear and distinct, and simple and complex arehere subtly different. Incontrovertibility (évidence, evidentia) in thetraditional sense is a feature of propositions derived from the senseswhich form the basis of syllogistic demonstration, whereas for Des-cartes it is to do with the immediacy of mental perception which isnot reducible to logical form, and which is ‘clear and distinct’ ofitself; prejudice, for scholastic philosophers, is described in morepositive terms as the prior knowledge of facts, or the meanings of

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words, or both (praenotio), and presupposed knowledge in the formof metaphysical principles and categories (form, matter, and priva-tion, act and potency, the four causes, for example), whereas Des-cartes sees all such mental baggage as noxious; the passage fromsimple to complex is seen in traditional terms as one from ‘thingsbetter known to us [through the senses]’ to ‘things known by theirnature’; this is explicitly reversed by Descartes in the title to thesecond edition of the Meditations, which reads ‘On the Nature of theHuman Mind, and That It Is Better Known Than the Body’. Here,and elsewhere, Descartes is dissociating his approach to knowledgefrom the famous Aristotelian adage ‘there is nothing in the mind thatwas not first in the senses’ (nil in intellectu quod non prius fuerit insensu). The passage from simple to complex is described usually interms of the relationship of terms to propositions. Descartes, on theother hand, is concerned with the rigorous development of know-ledge from its foundations, or the passage from elements to com-pounds. Even ‘not leaving anything out’ separates his undertakingfrom that of some branches of natural philosophy, in which natureis recognized to have residues and redundancies which would pre-vent its investigation in any formal mathematical way. Finally, ‘pos-iting’ is for Descartes not a procedure within logic by which a givenproposition is taken for the purposes of argument to be true; hissupposition is much closer to a step in the hypothetico-deductivemethod, the formulation of a hypothesis, consistent with generalprinciples, which then needs to be tested against empiricalobservations.35

The moral code, which has to be put in place because there can beno certainty in this area until the problems of epistemology (thetheory of knowledge) and ontology (the theory of being) have beensorted out, is in a similar way a combination of the familiar and thenew. The first rule is ‘to obey the laws and customs of my country,and to adhere to the religion in which God by his grace had meinstructed from my childhood, and to govern myself in everything

35 On these terms, see Étienne Gilson, Index scolastico-cartésien (Paris, );Jean-Luc Marion, Descartes: ‘Règles utiles et claires pour la direction de l’esprit en larecherche de la vérité’ (The Hague, ), glossary.

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else according to the most moderate and least extreme opinions,being those commonly received among the wisest of those withwhom I should have to live’; this makes reference to the virtue ofprudence, which in classical ethics governs moral and politicalbehaviour. The acceptance of custom, which Montaigne also advo-cated, gives value to entrenched social practices, and creates a pre-disposition to see moral and political values in local and relativeterms, which Descartes makes explicit in the text of the Discourse.The second and third rules are recognizably neo-Stoic:

to be as firm and resolute in my actions as I could, and to follow no lessconstantly the most doubtful opinions, once I had opted for them,than I would have if they had been the most certain ones; to endeavouralways to master myself rather than fortune, to try to change mydesires rather than to change the order of the world, and in general tosettle for the belief that there is nothing entirely in our power exceptour thoughts, and after we have tried, in respect of things external tous, to do our best, everything in which we do not succeed is absolutelyimpossible as far as we are concerned.

These rules recall strongly the opening sentences of the Enchiridion(a handbook of moral philosophy) of the ancient Stoic philosopher-slave Epictetus:

Some things are in our control and others not. Things in our control areopinion, pursuit, desire, aversion, and, in a word, whatever are our ownactions. Things not in our control are body, property, reputation, com-mand, and, in one word, whatever are not our own actions. The thingsin our control are by nature free, unrestrained, unhindered; but thosenot in our control are weak, slavish, restrained, belonging to others.Remember, then, that if you suppose that things which are slavish bynature are also free, and that what belongs to others is your own, thenyou will be hindered. You will lament, you will be disturbed, and youwill find fault both with gods and men. But if you suppose that only tobe your own which is your own, and what belongs to others such as itreally is, then no one will ever compel you or restrain you. Further, youwill find fault with no one or accuse no one. You will do nothing againstyour will. No one will hurt you, you will have no enemies, and you notbe harmed.

Such a philosophy of self-sufficiency was popularized in France in

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the years following its calamitous religious wars by such writers asGuillaume Du Vair (–), who translated Epictetus intoFrench, and whose frequently reprinted book On Constancy ()aspires to reconcile ancient Stoicism with Christianity, and stressesthe importance of controlling the will and developing a personalphilosophy as an antidote to the vicissitudes of fortune, the evils ofthe times, and the uncertainty of happiness. An international scholarwho had himself published a work with the title De constantia in, and who had much to do with the dissemination of these ideas,was Justus Lipsius; his Introduction to Stoic Philosophy (Manuductioad stoicam philosophiam) appeared in . The similarity of theseprogrammes to that put forward to Descartes is very striking; he wasto take its self-determining implications even further in his Passionsof the Soul, where he claims that ‘there is no soul so feeble that,correctly governed, cannot acquire an absolute mastery over its pas-sions’ (AT . –).

Part Four: Metaphysics and EpistemologyDescartes was very aware that his metaphysics and epistemology, aswell as the account of nature which flowed from them, were veryradical. He did not think that this would be as much a problem forthose amongst his readers who were not university-educated, andwho would have no vested interest in protecting entrenched philo-sophical positions; but even in their case, when he came to introducethe first part of the Meditations, he advised them to ‘devote severalmonths, or at least weeks, to considering the topics dealt with, beforegoing on’ (AT . ). He rightly saw that the learned community,who would be more familiar with the material, would find what hehad to say even more difficult to accept. Writing to Mersenne on January , he expressed the hope ‘that my readers will get used tomy principles without perceiving that they are doing so, and beforethey notice that my principles destroy those of Aristotle’ (AT .). Whereas the implicit message––that anyone could undertakethe journey of self-discovery and the discovery of God and theworld––would be seen as liberating by non-specialist readers, profes-sional philosophers would balk at a form of reasoning that couldnot be reduced to syllogistic logic, would reject a representation of

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the thinking human being which ignored almost all of traditionalfaculty psychology, and would jib at baffling new accounts of thesoul, of the relationship of mind to body, and of that of matter tothought and action.

There is a massive philosophical literature on the aspect ofDescartes’s thought which is summarily expounded in Part Four ofthe Discourse, and set out with great care in the Meditations; I shallindicate in the Explanatory Notes specific difficulties that wereperceived by his learned contemporaries in what he has to say. Iwant here to indicate what was seen to be problematic in generalterms. Part Four opens by applying ‘methodical doubt’ to humanclaims for knowledge of any kind; this has been linked to the voguefor scepticism in Descartes’s day, and has been seen as his answerto a crisis in early modern thought, in which Descartes used thefavoured weapon of atheists against themselves. This account isnow seen as not wholly satisfactory. There is, after all, nothingparticularly new in beginning a quest for certainty by calling intoquestion as much as one can, and certainty is indisputably Des-cartes’s quarry: ‘there are already so many views in philosophywhich are no more than plausible and which can be maintained indebate,’ he wrote in the letter to Mersenne in November citedabove, ‘that if my views have no greater certainty than that andcannot be approved of without controversy, I refuse ever to publishthem’ (AT . –; also . –). ‘Approved of without contro-versy’ refers to what in Descartes’s day was known as ‘probable’knowledge; this epithet was mainly used at this time to indicate nota judgement of relative frequency, but an argument from authoritybased on the judgement of the experts in any given field. Descartesclearly had no time for other experts, but still evokes here theprinciple of uncontroversially approved knowledge, as he believesthat his own metaphysical foundations will command assent oncethey are known.

In traditional terms, certainty was established by the use ofsyllogistic logic; in its place, Descartes uses a form of immediateintuition which cannot be reduced to proposition, middle term, andconclusion. One of the standard scholastic examples of the strongest(first) figure of syllogistic reasoning is the following:

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Everything having large extremities is strong (all B is A)All lions have large extremities (all C is B)

All lions are strong (all C is A)

When Descartes was invited later in his life to consider setting outhis philosophy in such conventional terms, he first argued that itwould be an immensely inefficient way of doing so (‘if I haddecided to deduce all of this in the form of logical argument, Iwould have worn out the hands of the printers and the eyes of myreaders by producing a huge tome’, he wrote to one of his cor-respondents in October : AT . –); later, in an interviewhe gave to the young Dutch scholar Frans Burman (–), hewent further, and contended that it was not only a cumbersome, butalso an erroneous, way to do it (AT . ). Burman wonderedwhether the ‘cogito’ (Descartes’s assertion that ‘I am thinking there-fore I exist’––(cogito ergo sum) was reducible to a syllogism in thefollowing form:

Whatever is thinking existsI am thinking

Therefore I exist

Descartes had already refuted this reductive account in his reply tothe second set of Objections to the Meditations:

When someone says ‘I am thinking therefore I am or exist’, he does notdeduce existence from thought by means of a syllogism but recognizes itas something self-evident by a simple intuition of the mind, as is clearfrom the fact that if he were deducing existence by means of a syllogism,he would have to have had previous knowledge of the major premise‘Everything which is thinking is, or exists’; yet in fact he rather learns itfrom experiencing in himself that it is impossible for him to think withoutexisting. (AT . )

His opponents retorted that when his arguments were trans-

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lated into traditional syllogistic terms, they were exposed ascircular.36

Even if some of his contemporaries were prepared to accept theimmediacy of the intuition ‘I am thinking, therefore I am’, theystill found problems with the version of mind and of self-enquirywhich it implies. In traditional terms, the intellect as it thinks ispresent in the human being in at least two modes, active and pas-sive; it is part of a complex procedure of retrieving and transmit-ting knowledge, which begins with the image (species) of the objectintended by the intellect, which passes into the brain through thesenses, is gathered in a ‘common sense’ (sensus communis) that poolsall the information available, then translated into intelligible form bythe passive intellect, and finally taken up as a concept by the agentintellect. This version of perception is hylomorphic: that is, it com-bines matter and form, the sensible and the intelligible. Descartes,on the other hand, insists on the immaterial character of all thought.The mental faculties of reason, imagination, and memory are locatedin traditional terms in the ventricles of the brain, both imaginationand memory having a material component; Descartes refers to thesefaculties, but categorizes them as ‘thinking substance’ (res cogitans),and denies them material being or locality. The immaterial thinkingego is set against the material world, which is no longer described interms of elements in various combinations and compositions, butinstead only as ‘extended substance’ (res extensa). The second half ofthe formula ‘I am thinking, therefore I am’ is an affirmation byDescartes not only of essence, but also of existence; in traditionalterms, essence and existence are separately conceived. What Des-cartes says was not unintelligible to his contemporaries, but it wasprofoundly radical; it dispensed with many of the presuppositions ofAristotelian metaphysics and psychology.37

36 See John Cottingham, Descartes (Oxford and Carlton, Va., ), – (on thecogito in syllogistic form), – (on the circle); Louis E. Loeb, ‘The Cartesian Circle’,in The Cambridge Companion to Descartes, ed. John Cottingham (Cambridge, ), –; and Étienne Gilson, René Descartes: Discours de la méthode: texte et commentaire,Paris, )) –.

37 See the various contributions in The Cambridge History of Renaissance Philosophyed. Charles B. Schmitt, Quentin Skinner, and Eckhard Kessler (Cambridge, )–.

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Some of Descartes’s first readers were not convinced of thenovelty of his proof of God’s existence, which follows from theintuition of his own. These critics pointed to the similarity ofthe ‘cogito’ to an argument in St Augustine, and indicated the (prob-ably unfair) parallel which might be drawn between the famousontological proof of God’s existence (the argument that the conceptof God entails His real existence, first formulated by St Anselm andbest known through its rehearsal in Aquinas’s Summa Theologiae)and Descartes’s argument that the ego’s intuition of its imperfectionnecessarily implies knowledge of a pre-existent perfect deity. Hisclaim that the soul is immaterial was also seen as not particularlynovel; it touched upon a very active contemporary debate concern-ing the immortality of the soul. Various exegetes of Aristotle, mostnotably the medieval Arabic philosopher Averroes and the second-century commentator Alexander of Aphrodisias (whose relevantworks had first been made available in the fifteenth century), hadargued that Aristotle held the soul to be material, and to die withthe body; this view was declared to be heretical by the Church atvarious times, notably in a decree of the Fifth Lateran Council of, which required all Christian philosophers to demonstratethrough philosophical (not theological) argument that the soul wasimmortal and immaterial. The offending interpreter of Aristotle atthat time was the Italian professor Pietro Pomponazzi (–);his treatise on the subject was reissued in , probably in Paris, inthe wake of the libertine ferment of the s. This had provoked areaction in the form of a number of vernacular defences of thesoul’s immortality and Aristotle’s subscription to this belief, includ-ing those by the Jesuit Louis Richeome (–) and Des-cartes’s acquaintance Jean de Silhon. Descartes himself was madeaware by Mersenne of some of the materialist libertine tracts circu-lating more or less clandestinely in Paris (AT . , , , ),and, in the introduction to his Meditations of , was to makereference to the decree of and to the need to argue for thesoul’s immortality (AT . ); in fact he does not set out here toprove more than its immateriality. But it may have been the cur-rency of the debate about the soul’s immortality which causedMersenne to add the words to the title of the first, Parisian, edition

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of the Meditations, ‘in which the existence of God and theimmortality of the soul are demonstrated’ (AT . ); these werechanged in the subsequent Amsterdam edition of , for whichDescartes was responsible, to the more accurate claim: ‘in whichthe existence of God and the distinction between the human souland the body are demonstrated.’ The earlier version of the titleshows how Descartes’s work could be reduced against the wishes ofits author to the terms of a current debate, and its novelty andprecision misrepresented.38

Part Five: Physics and PhysiologyDescartes’s two planned works, The Universe and Man, were to havebeen an account of a new departure in natural philosophy. There hadbeen radical rethinkings before him of Aristotelian physics: in aletter to Beeckman of October , Descartes himself mentionssuch names as Bernardino Telesio (–), Giordano Bruno, andTommaso Campanella (AT . ), although that does not indicatenecessarily that he had read their works attentively (or at all). In PartFive of the Discourse, Descartes sets out in very summary terms theargument of his Universe, gives an account of the operation of theheart, and sets down his theory of the difference between animalsand man. Various elements of mechanical philosophy emerge fromthese accounts: first, all natural phenomena proceed from a combin-ation of matter and movement, and can be explained in terms ofshape, size, quantity, and motion; second, all natural beings operatelike machines, and obey universal physical laws which are reducibleto mathematical terms; third, all bodies are made up of corpuscleswhich are too small to be perceived, which (depending on the theor-

38 Both Mersenne (as revealed by Descartes’s letter to him of May : AT. ), and Antoine Arnauld in his objections to the Meditations (AT . ) point tothe fact that a similar argument appears at various points in St Augustine’s writings: Delibero arbitrio, . . ; De civitate Dei, . ; also De trinitate, . . . On the immortal-ity of the soul, see Eckhard Kessler, ‘The intellective soul’, in The Cambridge History ofRenaissance Philosophy, –. Descartes’s determination that the memory is imma-terial removes one of the difficulties of conceiving of the individual soul after death, asin traditional terms its separation from the body would have removed access to thememory which was materially located in it: see the letter to Huygens of Oct. (AT . ).

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ist) may or may not be infinitely divisible, and may circulate either ina plenum or in a vacuum (the former of these alternatives beingDescartes’s claim).

In his later works, Descartes was to elaborate a mechanical phil-osophy which was axiomatic in structure, running from the sim-plest principles of human knowledge in a continuous series; bydefining matter solely in terms of extension, he would be able toclaim that physics could be based on the geometrical analysis ofbodies in motion. Such ideas are not spelt out systematically in theDiscourse; rather, the operation of the heart and the nature ofanimals as opposed to man are used to exemplify rather than demon-strate the explanatory force of the mechanical philosophy.Descartes’s contemporaries would not have had difficulty in grasp-ing what he says, new though it was, as the letter setting outobjections to his ideas possibly written in February shows (AT. –). The areas he discusses were widely debated at the time(he himself refers to Harvey’s book on the circulation of the blood,to which he grants qualified approval, unlike many of his con-temporaries); the issues involved were well known to both Aristote-lians and those who were interested in ancient atomism, such asPierre Gassendi (–), the author of the fifth set of Objec-tions to the Meditations (AT . –). In Descartes’s account,the role of the animal spirits as particles which pass through aspecific gland (the pineal gland) in the brain, where the immaterialsoul can interact with them, is crucial to his mechanical model ofthe human body. Descartes sets out here in a worked example whathe was able later, in his Principles of Philosophy of , to offer ingeneral terms, in a form somewhere between a textbook and asequence of demonstrations in the manner of classical geometry, asa radical and coherent alternative to the natural philosophy he hadbeen taught at school.39

39 William Harvey, Exercitatio anatomica de motu cordis et sanguinis in animalibus(Frankfurt, ) English translation, An Anatomical Disputation Concerning theMovement of the Heart and Blood in Living Creatures, trans. and introd. GwenethWhitteridge (Oxford, ); Daniel Garber, Descartes’s Metaphysical Physics (Chicago,).

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The Essays Published With the Discourse: Dioptrics,Meteorology, Geometry

It is important to remember that the book that came on to the marketin was not a slim pamphlet delineating the whole of Descartes’sphilosophy: it was a stout quarto of more than pages, includingthree essays illustrated with expensive diagrams, to which the open-ing discourse was a brief introduction, intended to illustrate thebenefits of Descartes’s new way of thinking and rigorous method.The first two of these essays are addressed to the general reader (whowould have been able to follow the Discourse, as I have tried to show);the Dioptrics addresses in turn the physical nature of light, refraction(the law of which, as has already been pointed out, Descartes was notalone in discovering in his generation), the physiology and optics ofthe eye, the relation of the senses to the nervous system and thebrain, retinal images, vision, and the means of its correction. Inaccordance with his programmatic claim that man could enhance hisunderstanding and exploitation of nature by invention, Descartesconsiders finally the best technique for grinding lenses, and theiroptimum shape.

The Meteorology addresses various phenomena––clouds, mists,and miasma; rain, hail, and snow; storms, thunder, and lightning;celestial events such as the appearance of ‘false’ suns (parhelia)––with a view to discovering explanations of them which do not relyon supernatural intervention of any kind, and accord with Des-cartes’s physics, which is anti-atomistic. There are also discourseson salts, rainbows, and colours. The subject-matter and the ques-tions considered have much in common with Aristotle’s Meteorologyand the relevant section of his Problems; Descartes even refers at onepoint, in an apparently conciliatory way, to scholastic discussionsderived from these texts: ‘In order to remain at peace with [trad-itional] philosophers, I don’t at all want to go against what theyimagine to be in these bodies in addition to what I have spoken of,such as their substantial forms and real qualities and suchlike, but itseems to me that my arguments should be more acceptable in that Ihave made them depend on fewer things’ (AT . ). It is notdifficult to detect the scorn behind this remark directed at such

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metaphysical baggage; this is made explicit in a letter to Regius ofJanuary , in which Descartes takes his disciple to task for reject-ing substantial forms and real qualities in a polemical way, andrecommends that he follow the less confrontational strategy of theMeteorology by producing new arguments without rejecting or deny-ing traditional accounts, simply setting these aside as unnecessaryfor current explanatory purposes (AT . ). The nature of thephenomena discussed by Descartes was also debated in French inthe Bureau d’Adresse, and by Mersenne in his Questions; but Des-cartes’s minimalist processes of explanation contrast with what is tobe found either there, or in such successful works as Cornelis Dreb-bel’s (–) Treatise on the Nature of the Elements, which firstappeared some twenty years before, and was widely diffused in vari-ous languages.40

In the final section of the Discourse, Descartes comments on theproof system of the first two essays in the following way: ‘it seems tome that my arguments follow each other in such a way that if the lastare proven by the first, which are their causes, the first are recipro-cally proved by the last, which are their effects’ (AT . ). Thiswould have struck a chord with contemporary natural philosophers,who were aware of a logical procedure known as regressus, by which aproof whose conclusion is a cause (demonstratio quia) is translatedinto one whose conclusion is an effect (demonstratio propter quid), thelatter being superior, as it is more ‘scientific’ to argue from causesthan from effects. Its standard example in natural philosophy is thefollowing:

Demonstratio quia Major Non-twinkling things arenear

Minor (effect) Planets are non-twinklingthings

Conclusion (cause) Planets are near

40 See above, n. ; Drebbel appeared in Dutch, German, and Latin between and at various printing centres.

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The passage from the first to the second syllogism marks also thepassage from the ‘order of discovery’ (ordo inveniendi) to the ‘orderof teaching’ (ordo docendi). It has already been pointed out that theMeditations ask the reader to follow the process of discovery; not,however, from objective effects but from subjective intuition. WhenDescartes sets out proofs in the three essays which follow the Dis-course, he explicitly uses the model of geometrical presentation (fromaxioms upwards), which is pedagogical, but not in the manner ofnatural philosophy. It may seem that the rationalist Descartes isengaged in something similar to regressus, but in fact he is not: hewants his premises to be causal, and he argues from effect only toconfirm the cause, by a process akin to the hypothetico-deductivemethod mentioned above, as he makes clear in a letter to Morindated July (AT . –). This contrasts sharply with thepractice of the English empirical natural philosophers who werehis near-contemporaries, such as William Harvey, Thomas Willis,Robert Hooke, and Robert Boyle. Much later, the novelist AndréGide produced in the mouth of one of his characters an ironic com-ment on this process: ‘I’m willing for reality to support my thinking,like a proof, but not for it to precede it.’41

The third of the trio of essays, Geometry, is perhaps the most far-reaching. Descartes is here no longer addressing the non-specialist,as his note to the reader (quoted above) shows. He does not alwaysmake life easy even for his mathematically adept readers, for he alsowilfully omits some of the steps of his demonstrations and some oftheir consequences, as his final comment reveals: ‘I hope that future

Demonstratio propterquid

Major What is near is non-twinkling

Minor (cause) Planets are near

Conclusion (effect) Planets do not twinkle

41 Aristotle, Posterior Analytics, i. a –a; Nicholas Jardine, ‘The Epis-temology of the Sciences’, in The Cambridge History of Renaissance Philosophy, –;Gide, Les Faux-monnayeurs, ed. J. C. Davies (London, ), : ‘je consens que laréalité vienne à l’appui de la pensée, comme une preuve, mais non point qu’elle laprécède.’

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generations will be grateful to me not only for the things I haveexplained in these pages, but also for those I have deliberately leftout, in order to leave them the pleasure of discovering them’ (AT .). Whether some of his correspondents were grateful to him forsetting problems either too difficult for them, or lacking all theinformation necessary for a solution, is another question. This shortwork marks the moment––presaged in works by various other math-ematicians, or actually accomplished before this date in unpublishedwritings such as those of Thomas Harriot (?–)––at whichgeometry and algebra ceased being separate. Descartes’s treatisemakes connections between algebra and geometry which enable thesolution of algebraic problems geometrically, and geometrical prob-lems algebraically; it is the precursor of what now would be called‘analytical geometry’. Descartes’s mathematics is presented in amore elegant, flexible, and developable notation than used by previ-ous generations, with a more successful use of diagrams, and abroader range of expressions, including those for negative andimaginary numbers and variables. Whereas most of the rest of hiswork, whether physical or philosophical, has been challenged or dis-credited, parts of the mathematics have proved to be an enduringintellectual legacy.42

Descartes as a Writer

It would not be appropriate here to engage in a detailed analysis ofDescartes’s French, but it is pertinent to point to one or two featuresof his style. It has often been praised for its clarity and restraint;indeed, it contrasts markedly with that of his friend Guez de Balzac,which is orotund and florid by comparison. Another writer ofsimilarly lucid and rigorous French, a century before, was thereformer Jean Calvin (–): like Descartes, he had undergone atraining in the law, which had bred in him caution and subtlety in hisuse of causal connectives, negatives, disjunctives, and conjunctives,and had made him aware of the distinction between proper and

42 On Harriot, see Thomas Harriot: An Elizabethan Man of Science, ed. Robert Fox(Aldershot, ).

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improper signification, the pitfalls of definition, and the vices ofambiguity and obscurity. This caution is detectable in Descartes’sclear but complex syntax; he has a predilection for subordinateclauses and qualifications; he shows great care in expressing pre-conditions and causal relations, often preferring the weakest designa-tions––‘for’, ‘in so far as’, ‘seeing that’––to ‘since’ and ‘because’; andhe is very adept in the use of negation, double negation, and even onoccasion triple negation. These features of his style, which to a smalldegree have been attenuated in this translation in the interests ofease of reading, also reflect his precise and fastidious nature, with itspreoccupation with truth and accuracy.

There are clear signs that he was trying to write accessibly andattractively; this is most evident in his use of sustained images. Asone would expect, Descartes has recourse to the commonplacemetaphor of philosophy as a building, although in a more restrainedway than that of some of his contemporaries, as illustrated by acomparison with this passage from Galileo’s Dialogue. In it, theItalian physicist has the enlightened modern philosopher Sagredoexpress his ironic sympathy for the hidebound scholastic Simplicio:

I pity Simplicio no less than I should some gentleman, who, having built amagnificent palace at great trouble and expense, employing myriads ofartisans, and then seeing it threatened with ruin because of poor founda-tions, should attempt, in order to avoid the sad sight of walls destroyed,adorned as they are with so many lovely murals; or columns fall, whichsupport the superb galleries, or gilded beams collapse, or doors, pedi-ments and marble cornices, supplied at so much cost, spoiled––shouldattempt to prevent the collapse with chains, props, buttresses, iron bars,and shores.43

In a similar way, Descartes quite frequently refers to the dangers ofbuilding on poor foundations (indeed, the Meditations open with a

43 Galileo, Dialogo sopra i due massimi sistemi del mondo, in Opere, ed. FerdinandoFlora (Milan, and Naples, ), . –: ‘io compatisco, [il signor Simplicio], nonmeno che a quel signore che, con gran tempo, con spesa immensa, con l’opera di cento ecento artefici, fabbricò nobilissimo palazzo, e poi lo vegga, per esser stato mal fondato,minacciar rovina, e che, per non vedere con tanto cordoglio disfatte le mura di tantevaghe pitture adornate, cadute le colonne sostegni delle superbe loggie, caduti i palchidorati, rovinati gli stipiti, i frontespizi e le cornici marmoree con tanta spesa condotte,cerchi con catene, puntelli, contrafforti, barbacani e sorgozzoni di riparare alla rovina.’

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reference to this image: AT . –); but he also puts architecturalimagery to more personal uses. The laborious and ineffective processof shoring up a philosophical system by its adherents is contrasted inthe Discourse with the much more successful procedure of planningsomething anew from the very beginning: ‘buildings which a singlearchitect has planned and completed’, Descartes avers, ‘are usuallymore beautiful and better designed than those that several architectshave tried to patch together, using old walls that had been con-structed for other purposes’ (AT . ). Galileo does not concernhimself with the question whether radical philosophical enterprisesare better engaged in collectively or singly; Descartes has no doubtthat the latter strategy is preferable, and makes this clear by hisreference to the time-wasting involved in working with enthusiasticcollaborators, who might either be dim and require much to beexplained to them, or alternatively precipitate in their judgements,and bring Cartesianism into disrepute through their ill-consideredsupport of the cause. The sustained analogy between philosophy andarchitecture is here made economically to serve Descartes’s ownpurposes.

Descartes also states that there is a role for the discarded materialsof discredited philosophical systems: just as one usually preservesbits of debris from the old building in order to reuse them in con-structing a new one, so also should one, in destroying all those opin-ions which are judged to be ill-founded, be prepared to reuse someof the elements on which they were based in establishing more cer-tain ones (AT . ). It would seem that this suggestion is not whollysincere, or rather, it is only sincerely meant in the sphere of ethicsand political behaviour. Descartes’s advice to Regius not to exacer-bate Aristotelians by confrontation where this is not necessary, citedabove, must be seen in the light of his private hope that they will notnotice the degree to which his thought is inconsistent with that ofthe prevailing scholasticism. In writing to his Jesuit master at LaFlèche, and in seeking the approbation of the Sorbonne (the theo-logical faculty of the University of Paris, to whom he dedicated theMeditations) and of that of Father Gibieuf, he seems to be hopingthat his own system will replace that of Aristotle, not that it shouldreconfigure parts of it. The only part of traditional thinking which is

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clearly retained is its overall arboreal structure (metaphysics as theroot, physics as the trunk, and ethics and medicine as the highestbranches); but even here, Descartes produces an innovation by hav-ing metaphysics considered before physics, whereas in the scholasticcurriculum metaphysics was taught later, even if it was looked uponas ‘first philosophy’.44

One specific feature of the reuse of old philosophical materialswhich Descartes addresses is lexical. In his metaphysics he employsterms such as ‘substance’, ‘essence’, and ‘existence’, but by makingexistence a feature of the thinking subject, from whose reflection theexistence of God is deduced, he alters radically the traditional rela-tionship between these terms. Equally, his radical separation of the‘thinking substance’ and the ‘extended substance’––what has cometo be known as his dualism––disrupts the semantic coherence ofmuch of the hylomorphic vocabulary of the schoolmen (‘form’,‘matter’, ‘substantial form’, ‘accident’, ‘quality’). Even the phrase‘clear and distinct’ in his usage, denoting what is sufficiently per-ceptible to the attentive mind to rule out confusion as to whatis perceived, is very different from its employment by near-contemporary logicians such as Jacopo Zabarella (–), forwhom it describes the effect of the agent intellect on the confusedsense impressions that are in the part of the mind designed to receivethem (the ‘common sense’). The Cartesian modifications of theseterms will be discussed in the Notes; the most important of them areitalicized in this translation (a practice espoused by Descarteshimself, albeit sparingly); there are also other terms that deserveseparate mention here, as they would have struck contemporaries asparticularly transgressive. The word ‘soul’ (as opposed to ‘mind’ or‘rational intellect’) does not refer in Descartes to the vitalistic prin-ciple or source of life of the scholastics; it is purely mechanical.‘Evidence’ is linked by Descartes to his notion of intuition, whichhe defines in the Rules as ‘the conception of a clear and attentivemind, which is so easy and distinct that there can be no roomfor doubt about what we are understanding’ (AT . ); for his

44 AT . –; letter to Father Guillaume Gibieuf of Nov. (AT . –), cf.AT . , ; Principes, AT B. (on the tree of knowledge).

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Aristotelian contemporaries, it is bound into a system of assessingthe demonstrative status of propositions, and is often linked tosensory information. Descartes uses terms such as ‘plausible’ and‘probable’ to denote unacceptable levels of uncertainty; his scholasticcontemporaries recognized that the degree of truth attainable in vari-ous areas of knowledge could never aspire to a higher status than this,and were content with it. Finally, thought, as has been pointed out, isboth enriched as a term, designating both the process of knowing andits product, and covering as it does imagining, willing, and so on; andimpoverished, as it is cut free from the process by which knowledgeis acquired from the senses. The overall effect would have struckDescartes’s contemporaries as a form of re-description which is atthe same time a re-evaluation, or, to use a term of art from rhetoricwhich has recently been given some prominence, ‘paradiastole’.45

As well as the metaphor of architecture, Descartes exploits that ofthe journey and its parallel with encounters with the past (‘convers-ing with those of another age is more or less the same thing astravelling’) and with intellectual progress. From the opening ofSeneca’s De vita beata (‘On the Happy Life’: a book he recommendedto the Princess Elizabeth) he borrows the image of ‘those who goforward but very slowly, and who can get further, if they alwaysfollow the right road, than those who are in too much of a hurry andstray off it’ (AT . ). Elsewhere, he compares himself to ‘a manwalking by himself in the dark’, who decided ‘to go so slowly and toexercise such caution in everything that even if he made very littleprogress, he would at least be sure not to fall’ (AT . –). Tojustify his strict adherence to moral decisions once he had reachedthem, Descartes declares that he:

imitated those travellers who, finding themselves lost in a forest, must notwander in circles first to one side then to the other, and still less stop inone place, but have to walk as straight as possible in one direction, and notalter course for weak reasons, even if it might only have been chancewhich had led them to settle on the direction they had chosen; for by this

45 See above n. ; on paradiastole, see Quentin Skinner, ‘Thomas Hobbes:Rhetoric and the Construction of Morality’, Proceedings of the British Academy, (), –.

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means, even if they do not end up precisely where they want to be, theywill eventually reach somewhere where they will most likely be better offthan the middle of a forest. (AT . –)

There is nothing particularly original about these passages, butthey sit comfortably in the Discourse, and reinforce its nature as adocument accessible to all.

Other images popular in his day find their way into the Discourse,and have the same function: the world is a stage on which dramas areplayed out; philosophers are like ‘military commanders whose forcesusually grow in proportion to their victories, and who need moreskill to maintain their position after defeat in battle than they need totake towns and provinces after a victory. For to try to overcome allthe problems and errors that prevent us attaining knowledge of thetruth is indeed to engage in battle’ (AT . , ). Ignorance isdarkness or blindness; light is knowledge or insight: ‘so it was that Ifreed myself gradually from many of the errors that can obscure thenatural light of our minds’; ‘God has given each of us an inner lightto distinguish the true from the false’; Aristotelians are ‘like blindmen who, in order to fight on equal terms against those who can see,lure them into the depths of some very dark cellar’. This last image,like many in Descartes’s writing, is a sustained simile: ‘I may say thatit is in the interest of these people that I abstain from publishing theprinciples of philosophy that I use; for as they are very simple andvery certain, I would be doing the same in publishing them as open-ing some windows, and letting the light of day into the cellar intowhich they have gone down to fight’ (AT . , , ). But it issustained in a very controlled way; unlike Galileo, whose fine build-ing on insecure foundations is expanded for the sake of creating arich and detailed picture for the pleasure of the reader as opposed tosubserving an analogy, Descartes does not allow similes and meta-phors to run away with him. They are controlled, sober, and pre-cisely employed, and reflect the thought which they are there tomediate.

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Envoi: The Cartesian Philosophical Edifice

Some time ago, a cartoon purporting to illustrate the differencebetween the French philosophical tradition and Anglo-Americananalytical philosophy appeared in the pages of the magazine Punch.It portrayed French philosophy as a phantasmagorical multi-turreted castle resting precariously on such narrow foundations thatthe whole image resembled an inverted pyramid; Anglo-Americananalytical philosophy, by contrast, was represented as a plain brick,on which a philosopher was hesitantly planning to place another.This neatly caricatured the propensity to unfettered rationalistabstract speculation of the French tradition on the one hand, and theover-cautious approach of the Anglo-American tradition on theother––a comparison which the historian of physics Pierre Duhemexpressed in terms more favourable to the French, by contrastingtheir ‘profound mind’, marked by its penchant for generality andabstraction, with the capacity of the English to see ‘picturesquedetails’ in a concrete way, but to compose explanations of givenphenomena which may not have any overall coherence.46

While it is likely that the British cartoonist had the flights ofexistentialist fancy of Sartre more in his mind than the work ofDescartes, it plausible that he would have seen the latter, a self-declared ambitious system-builder, as a legitimate target also. Yetmany distinguished adherents of Anglo-American analyticalphilosophy recognize Descartes as a founding father of good philo-sophical practice––the cautious placing of one brick on another, thepatient and thorough examination of the validity of arguments––and he is still used as a text on which first-year undergraduates inGreat Britain and America are made to cut their teeth. Moderncommentators from both sides of the Channel are united in applaud-ing the rigour and discipline of his thought, even if they perceiveparts of it to contain errors of reasoning or problems of implication.Descartes’s philosophical enterprise is captured by neither compon-ent of the cartoonist’s caricature, or perhaps by both. He certainlyset out to build a whole system which would eventually reach newheights of philosophical achievement, but he also believed in the

46 Pierre Duhem, La Théorie physique (Paris, ), –.

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need for irrefragable foundations. If he had completed his life’swork, he would have hoped to be able to show that from the immedi-ate intuition of the thinking self, a system could be constructedwhich would offer a way (when combined with the hypothetico-deductive method) both to set about accounting for the natural worldas it is, and to manipulate it for man’s own ends; at its topmost levelit would support a perfect medical science, with its guarantee ofhealth and longevity, and an ultimate version of ethics, with itspromise of tranquillity of mind and happiness. This is the pro-gramme which the Discourse sets out, and which Descartes’s sub-sequent publications confirm. While one must acknowledge that hefailed to achieve his philosophical goals, and was wrong in many ofhis ‘scientific’ claims, one cannot but admire the intellectual scopeand ambition of his enterprise.

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NOTE ON THE TEXT

The text which has been used for this translation is that inDescartes, Œuvres complètes, ed. Charles Adam and Paul Tannery, vols. (Paris, ), referred to as AT in the Introduction and Notes.The Discours de la méthode appears in vol. , pp. –. It is repro-duced by Étienne Gilson, René Descartes: Discours de la méthode:texte et commentaire (Paris, ).

The marginal numbers refer to the pages of the AT edition.Asterisks signify an editorial note at the back of the book.

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SELECT BIBLIOGRAPHY

There is a vast amount of material on Descartes; below are some(mainly English-language) texts which may be found useful amongmany others.

EditionsŒuvres, vols., ed. Charles Adam and Paul Tannery (Paris, ).The Philosophical Writings Of Descartes, vols. and , trans. John

Cottingham, Robert Stoothoff, and Dugald Murdoch (Cambridge,); vol. , trans. the above and Anthony Kenny (Cambridge,).

BiographiesAdrien Baillet, La Vie de Monsieur Descartes, vols. (Paris, ).Stephen Gaukroger, Descartes: An Intellectual Biography (Oxford,

).Geneviève Rodis-Lewis, Descartes: His Life and Thought, trans. Jane

Marie Todd (Ithaca and London, ).

General BackgroundThe Cambridge History of Renaissance Philosophy, ed. Charles B.

Schmitt, Quentin Skinner, and Eckhard Kessler (Cambridge, ).The Cambridge History of Seventeenth-Century Philosophy, vols., ed.

Daniel Garber and Michael Ayers (Cambridge, ).

Critical Guides and Secondary Literature

Collections of Essays

The Cambridge Companion to Descartes, ed. John Cottingham(Cambridge, ).

Descartes, ed. John Cottingham (Oxford, ).Descartes: A Collection of Critical Essays, ed. Willis Doney (London,

).Descartes: Critical and Interpretive Essays, ed. Michael Hooker

(Baltimore and London, ).

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Reason, Will and Sensation: Essays on Descartes’s Metaphysics, ed. JohnCottingham (Oxford, ).

Stephen Voss, Essays on the Philosophy and Science of Descartes(Oxford, ).

Individual StudiesRoger Ariew, Descartes and the Last Scholastics (Ithaca and London,

).Desmond M. Clarke, Descartes’s Theory of Mind (Oxford, ).John Cottingham, Descartes (Oxford, ).Edwin M. Curley, Descartes Against the Skeptics (Oxford, ).Daniel Garber, Descartes’ Metaphysical Physics (Chicago, ).Stephen Gaukroger, Descartes’ System of Natural Philosophy

(Cambridge, ).Anthony Kenny, Descartes: A Study of His Philosophy (Bristol, ).Tom Sorell, Descartes (Oxford, ).Bernard Williams, Descartes: The Project of Pure Enquiry (Harmonds-

worth, ).

GlossariesÉtienne Gilson, Index scolastico-cartésien (Paris, ).Jean-Luc Marion, Descartes: ‘Règles utiles et claires pour la direction de

l’esprit en la recherche de la vérité’ (The Hague, ).

Websitewww.cartesius.net Descartes E Il Seicento, maintained by Giulia

Belgioioso (Director, Centro Interdipartmentali Di Studi Su Des-cartes E Il Seicento), Jean-Robert Armogathe (Centre d’Étudescartésiennes), and their colleagues

Further Reading in Oxford World’s ClassicsBacon, Francis, The Essays or Counsels Civil and Moral, ed. Brian

Vickers.Berkeley, George, Principles of Human Knowledge and Three Dialogues,

ed. Howard Robinson.

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A CHRONOLOGY OF RENÉ DESCARTES

March: born at La Haye near Tours.

– Attends the Jesuit college of La Flèche.

Galileo’s observation of the four moons of Jupiter.

Licenciate of Law, University of Poitiers.

Joins the army of Prince Maurice of Nassau in Holland.

Moves to the army of Elector Maximilian, duke of Bavaria, inGermany.

November: dream of a ‘wonderful science’.

Publication of Bacon’s Novum Organum.

– Travels in Europe.

– Imprisonment of Théophile de Viau as ringleader of theParisian free-thinkers.

– Based in Paris, in the circle of Mersenne.

Publication of Harvey’s Circulation of the Blood.

(or ) Completion of Rules For the Direction of Our NativeIntelligence.

(end) Move to Holland.

Work on The Universe.

Publication of Galileo’s Dialogue Concerning the Two ChiefWorld Systems.

Condemnation of Galileo by the Roman Inquisition;Descartes abandons plans to publish The Universe.

Birth of Descartes’s natural daughter, named Francine,baptized August (died ).

Publication of A Discourse on the Method, with three essays:Dioptrics, Meteorology, and Geometry.

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Publication of Meditations, with the first six sets of Objectionsand Replies.

Publication of second edition of Meditations, with all sevensets of Objections and Replies. First contact with PrincessElizabeth of Bohemia.

Cartesian philosophy condemned at the University ofUtrecht.

Visit to France; publication of the Latin version of ThePrinciples of Philosophy (French translation ), and theLatin version of the Discourse and the Essays.

Award of a pension by the king of France; return to France toarrange its receipt. Publication of Comments on a CertainBroadsheet.

April: interview with Frans Burman at Egmond-Binnen. Beginning of the civil war known as ‘La Fronde’ in France. Journey to Sweden on invitation of Queen Christina;

publication of the Passions of the Soul. February: death in Stockholm from pneumonia. Descartes’s remains returned to France, to rest eventually in

Saint-Germain des Prés.

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A DISCOURSE ON THE METHODOF CORRECTLY CONDUCTING

ONE’S REASON ANDSEEKING TRUTH IN THE SCIENCES

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If this discourse seems too long to be read all at once,* it may

be split up into six parts. In the first will be found severalconsiderations relating to the sciences. In the second, theprincipal rules of the method that the author has found. In thethird, some of the moral rules he has derived from this method.In the fourth, the arguments by which he proves the existenceof God and of the human soul, which are the foundations ofhis metaphysics. In the fifth, the order of the physical questionshe has investigated, and particularly the explanation of themovement of the heart and some other problems pertaining tomedicine, as well as the difference between the human souland that of animals. And in the last part, the requirements hebelieves are necessary to make progress beyond that which hehas already made in the study of nature, and the reasons thatprompted him to write.

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PART ONE

Good sense* is the most evenly distributed thing in the world;for everyone believes himself to be so well provided with it that

even those who are the hardest to please in every other way donot usually want more of it than they already have. Nor is itlikely that everyone is wrong about this; rather, what thisshows is that the power of judging correctly and of dis-tinguishing the true from the false (which is what is properlycalled good sense or reason) is naturally equal in all men, andthat consequently the diversity of our opinions arises not fromthe fact that some of us are more reasonable than others, butsolely that we have different ways of directing our thoughts,and do not take into account the same things. For it is notenough to possess a good mind; the most important thing is toapply it correctly.* The greatest minds are capable of thegreatest vices as well as the greatest virtues; those who goforward but very slowly can get further, if they always followthe right road, than those who are in too much of a hurry andstray off it.*

For myself, I have never presumed my mind to be any waymore accomplished than that of the common man. Indeed, Ihave often wished that my mind was as fast, my imagination asclear and precise, and my memory as well stocked and sharp asthose of certain other people. And I personally know of no anyother mental attributes that go to make up an accomplishedmind;* for, as regards reason or good sense (insofar as it is theonly thing that makes us human and distinguishes us frombrute beasts), I am ready to believe that it is altogether com-plete in every one of us, and I am prepared to follow in this theagreed doctrine of those philosophers who say that differencesof degree apply only to accidents, and not to forms or natures of

individuals of the same species.*But I venture to claim that since my early youth I have had

the great good fortune of finding myself taking certain pathsthat have led me to reflections and maxims from which I havefashioned a method* by which, it seems to me, I have a way ofadding progressively to my knowledge and raising it bydegrees to the highest point that the limitations of my mindand the short span of life allotted to me will permit it to reach.For I have already reaped so many fruits from this method thatI derive the highest satisfaction from the progress that Ibelieve myself already to have made in my pursuit of truth, inspite of the fact that in appraising my own achievements I tryalways to err on the side of caution rather than that of pre-sumption, and that when I cast a philosopher’s eye over thevarious actions and undertakings of mankind, there is hardly asingle one that does not seem to me to be vain and futile.* AndI conceive such hopes for the future that if, among the purelyhuman occupations,* there is one that is really good andimportant, I venture to believe that it is the one that I havechosen.

It is, however, possible that I am wrong, and that I am mis-taking bits of copper and glass for gold and diamonds. I knowhow likely we are to be wrong on our own account, and howsuspect is the judgement of our friends when it is in ourfavour. Nonetheless, in this essay I shall gladly reveal the paths

I have followed and paint my life as it were in a picture, so thateveryone may come to a judgement about it; and from hearingthe reactions of the public to this picture,* I shall add a newway of acquiring knowledge to those which I habituallyemploy.

So my aim here is not to teach the method that everyonemust follow for the right conduct of his reason, but only toshow in what way I have tried to conduct mine.* Those whotake it upon themselves to give direction to others must believethemselves more capable than those to whom they give it, andbear the responsibility for the slightest error they might make.But as I am putting this essay forward only as a historicalrecord, or if you prefer, a fable, in which among a number of

examples worthy of imitation one may also find several whichone would be right not to follow, I hope that it may proveuseful to some people without being harmful to any, and thatmy candour will be appreciated by everyone.

I was educated in classical studies* from my earliest years,and because I was given to believe that through them onecould acquire clear and sure knowledge of everything that oneneeded in life, I was extremely eager to acquire them. But assoon as I had finished my course of study, at which time it isusual to be admitted to the ranks of the well educated, I com-pletely changed my opinion, for I found myself bogged downin so many doubts and errors, that it seemed to me that havingset out to become learned, I had derived no benefit from mystudies, other than that of progressively revealing to myselfhow ignorant I was. And yet I was a pupil of one of the most

famous schools in Europe, in which I believed that there mustbe as learned men as are to be found anywhere on earth. ThereI had learnt everything that others were learning; and not justcontent with the subjects that we were taught, I had even readall the books that fell into my hands on subjects that are con-sidered the most occult and recondite.* Moreover, I knewwhat assessment others had made of me, and realized that Iwas not thought inferior to my fellow pupils, even thoughseveral among them had already been singled out to take theplace of our teachers. And finally, our age seemed to me to beas flourishing as any preceding age, and to abound in as manygreat minds. This emboldened me to judge all others bymyself, and to think that there was no body of knowledge onearth that lived up to the expectations I had been given of it.

I did not, however, cease to hold the school curriculum inesteem. I know that the Greek and Latin that are taught thereare necessary for understanding the writings of the ancients;that fables stimulate the mind through their charm; that thememorable deeds recorded in histories uplift it, and they helpform our judgement when read in a discerning way; that read-ing good books is like engaging in conversation with the most

cultivated minds of past centuries who had composed them, orrather, taking part in a well-conducted dialogue in which suchminds reveal to us only the best of their thoughts; that oratoryis incomparably powerful and beautiful, and that poetry pos-sesses delightful delicacy and charm;* that mathematics has

very subtle techniques that can be of great use in satisfyingcurious minds, as well as in coming to the aid of all the arts,and reducing human labour; that books on morals containhighly instructive teachings and exhortations to virtue;* thattheology charts our path to heaven; that philosophy providesus with the means of speaking plausibly about anything andimpressing those who are less well instructed; that law, medi-cine, and other disciplines bring to those who profess themriches and honours;* and finally, that it is worthwhile to havestudied all of these branches of knowledge, even the mostsuperstitious and false, in order to learn their true value andavoid being deceived by them.

But I then decided that I had devoted enough time both tothe study of languages and to the reading of the books, histor-ies, and fables of the classical world. For conversing with thoseof another age is more or less the same thing as travelling. It isgood to know something of the customs of different peoples inorder to be able to judge our own more securely, and to preventourselves from thinking that everything not in accordance withour own customs is ridiculous and irrational, as those whohave see nothing of the world are in the habit of doing. On theother hand, when we spend too much time travelling, we endup becoming strangers in our own country; and when weimmerse ourselves too deeply in the practices of bygone ages,we usually remain woefully ignorant of the practices of ourown time. Moreover, fables make us conceive of events as

being possible where they are not; and even if the most faithfulof accounts of the past neither alter nor exaggerate the import-ance of things in order to make them more attractive to thereader, they nearly always leave out the humblest and leastillustrious historical circumstances, with the result that what

remains does not appear as it really was, and that those whobase their behaviour on the examples they draw from suchaccounts are likely to try to match the feats of knights of old*in tales of chivalry and set themselves targets beyond theirpowers.

I held oratory in high esteem, and loved poetry, but I lookedupon both as gifts of the mind rather than fruits of study.Those who reason most powerfully and are the most successfulat ordering their thoughts so as to make them clear and intelli-gible will always be best able to persuade others of what theysay, even if they speak in the thickest of dialects* and havenever learned any rhetoric. And those whose linguistic expres-sion is the most pleasing and who frame their thoughts in themost eloquent and agreeable way would always end up beingthe best poets, even if they did not know a single rule of poeticcomposition.

I was most keen on mathematics, because of its certaintyand the incontrovertibility* of its proofs; but I did not yet see itstrue use. Believing as I did that its only application was to themechanical arts,* I was astonished that nothing more exaltedhad been built on such sure and solid foundations; whereas, onthe other hand, I compared the moral works of ancient paganwriters to splendid and magnificent palaces built on nothing

more than sand and mud. They exalt the virtues, and makethem seem more worthy of esteem than anything else on earth;but they do not give sufficient indication of how to learn aboutthem; and what they call by such a fine name is in many casesno more than lack of human feeling, pride, despair, orparricide.*

I revered our theology and hoped as much as anyone toreach heaven; but having learnt as an established fact that thepath to heaven is as open to the most ignorant as to the mostlearned, and that the revealed truths that lead there are beyondour understanding, I would not have dared submit them to myown puny reasoning powers, and believed that in order toengage in the task of studying them, it was indispensable to

have some extraordinary assistance from heaven, and to bemore than merely human.*

I shall not say anything about philosophy except that, whenI realized that it had been cultivated by the best minds formany centuries, and that nevertheless there is nothing in it thatis not disputed and consequently is not subject to doubt, I wasnot so presumptuous as to hope to succeed better than others;and that seeing how different learned men may defend differ-ent opinions on the same subject, without there ever beingmore than one which is true, I deemed anything that was nomore than plausible* to be tantamount to false.

As for the other disciplines, in so far as they borrow theirprinciples from philosophy, I concluded that nothing solid

could have been built on such shaky foundations. Nor was thehonour and the profit they held in prospect enough to per-suade me to study them; for I considered myself, through thefavour of providence, as not being in the position of having toearn my living from a learned profession for the betterment ofmy fortune; and although I did not go about sneering atworldly glory as is the habit of Cynics,* I nonetheless held thatsort of glory, to which I could never hope to have a true claim,in low esteem. Finally, as for the low sciences,* I felt that Ialready knew well enough what they were worth to avoid fall-ing for any of the promises of an alchemist, the predictions ofan astrologer, the impostures of a magician, or the tricks andboasts of those who profess to know more than they do.

That is why, as soon as I reached an age that allowed me toescape from the control of my teachers, I abandoned altogetherthe study of letters. And having decided to pursue only thatknowledge which I might find in myself or in the great book ofthe world, I spent the rest of my youth travelling, visitingcourts and armies, mixing with people of different characterand rank, accumulating different experiences, putting myselfto the test in situations in which I found myself by chance, andat all times giving due reflection to things as they presentedthemselves to me so as to derive some benefit from them. For it

seemed to me that I could discover much more truth from thereasoning that we all make about things that affect us and that

will soon cause us harm if we misjudge them, than from thespeculations in which a scholar engages in the privacy of hisstudy, that have no consequence for him except insofar as thefurther they are from common sense, the more he will beproud of them, because he has had to use so much moreingenuity and subtlety in the struggle to make them plausible.And I constantly felt a burning desire to learn to distinguishthe true from the false, to see my actions for what they were,and to proceed with confidence through life.

It is true that while I was thinking about the customs ofother men and nothing else, I found little to provide me withcertain knowledge; I observed in them as much diversity as Ihad found earlier among the opinions of the philosophers. Andso the greatest benefit I derived from these observations wasthat when I was confronted by things which, although theyseem to us very extravagant and ridiculous, are neverthelesswidely accepted and approved of by other great nations, Ilearned not to believe too firmly in anything that only exampleand custom had persuaded me of.* So it was that I freedmyself gradually from many of the errors that can obscure thenatural light of our minds, and make them less able to seereason. But after having spent several years studying the bookof the world and trying to acquire some experience of life, Itook the decision one day to look into myself and to use all mymental powers to choose the paths I should follow. In this itseems to me that I have had much more success than if I had

never left either my country or my books.

PART TWO

At that time I was in Germany, where I had been called by thewars that have not yet come to an end there; as I was returningto the army from the coronation of the emperor, I was haltedby the onset of winter in quarters where, having no divertingcompany and fortunately also no cares or emotional turmoil*to trouble me, I spent the whole day shut up in a small roomheated by a stove, in which I could converse with my ownthoughts at leisure.* Among the first of these was the realiz-ation that things made up of different elements and producedby the hands of several master craftsmen are often less perfectthan those on which only one person has worked. This is thecase with buildings which a single architect has planned andcompleted, that are usually more beautiful and better designedthan those that several architects have tried to patch together,using old walls that had been constructed for other purposes.This is also the case with those ancient cities, that in thebeginning were no more than villages and have become,through the passage of time, great conurbations; when com-pared to orderly towns that an engineer designs without con-straints on an empty plain,* they are usually so badly laid outthat, even though their buildings viewed separately oftendisplay as much if not more artistic merit as those of orderlytowns, yet if one takes into consideration the way they aredisposed, a tall one here, a low one there, and the way theycause the streets to wind and change level, they look more like

the product of chance than of the will of men applying theirreason. And if one considers further that there have alwaysbeen officials whose task it was to ensure that the design ofprivate buildings should contribute to the beauty of the townas a whole, it will become clear how difficult it is to carryanything through to completion when working only with whatothers have produced. This led me to the view that those

nations who were once half-savage and only gradually becamemore civilized, and whose legislation was forced on them byacts of criminal mischief and legal disagreements, could not beas well governed as those which, from the first moment oftheir coming together as a nation, observed the constitutionlaid down by a prudent lawgiver; in the same way, it cannot bedoubted that a state which has embraced the true religionwhose laws God alone has made must be incomparably bettergoverned than any other. To return to human affairs, I believethat if Sparta once flourished greatly, it was not because of theparticular excellence of each one of its laws (seeing that manywere very strange and even contrary to good morals*), butbecause having all been laid down by one man,* they were alldirected to a single end. And so I came to believe that book-learning, or at least learning whose rational foundations are nobetter than generally approved, and which contains no realproof, is not as close to the truth, composed as it is of theopinions of many different people, as the simple reasoning thatany man of good sense can produce about things in his pur-

view. And so, although I came to believe that, because we werechildren before we were men, and because for a long time wewere governed by our appetites and our teachers (the formerbeing often in conflict with the latter, with neither giving thebest advice in every case), it is almost impossible that ourjudgements are as pure or as solid as they might have been ifwe had had full use of our reason from the moment of ourbirth, and had been guided by that alone.*

Admittedly, we do not see people pulling down all thehouses of a town for the sole purpose of reconstructing themdifferently in order to embellish the streets; but we do seemany people having their own houses demolished in order torebuild them, and may note that they are even sometimesforced to do so when the buildings are in danger of fallingdown of themselves or their foundations are insecure. Thisexample convinced me that it would not be reasonable for anindividual to set out to reform a state by changing everything

from the foundations up, and overthrowing it in order torebuild it, or even to set out to reform the body of knowledgeor the established order in schools for teaching it;* but rather,as far as all the opinions I had hitherto accepted were con-cerned, I could do no better than to set about ridding myself ofthem once and for all, with a view to replacing them afterwardseither with better ones, or even the same ones, once I had

tested them with my reason and ensured that they were setstraight. I firmly believed that by these means I would manageto order my life better than if I built on old foundations andrelied only upon old principles which had been inculcated inme when young, without my ever having sought to find outwhether they were true. For although I could see a number ofdifficulties in all this, they were not unsurmountable; nor didthey compare with those which are found in the smallestreform affecting the body public. Such a great body is too hardto rebuild if once destroyed, or even to keep standing if onceshaken, and its fall cannot be anything other than very heavy.Moreover, as for any imperfections such bodies may have (andtheir very diversity is sufficient to ensure that some at least willhave imperfections), custom may have considerably attenuatedthem, and even managed to circumvent or imperceptibly tocorrect many that could not have been so well remediedthrough the exercise of political judgement.* Finally, theseimperfections are nearly all more bearable than change, in thesame way that highways that wind their way between moun-tains become in the end so smooth and easy through use that itis much better to follow them than to attempt to seek astraighter path, by climbing over rocky promontories andplunging down into deep valleys.

That is why I could not possibly approve of those meddle-some and restless spirits who are called neither by birth nor byriches to take part in public affairs, yet are forever plottingsome reform. And if I thought that there was anything what-

soever in this essay that could lead me to be suspected of thesame folly, I should be very loath to allow it to be published.

My project has never extended beyond wishing to reform myown thoughts and build on a foundation which is mine alone.And if my work has pleased me enough for me to reveal to youhere what it is based on, I do not want for all that to suggestthat anyone should copy it. Those on whom God has bestowedHis grace in greater measure will perhaps have more loftydesigns;* but I very much fear that mine may already be toobold for many. Even the decision to rid oneself of all the opin-ions one has hitherto accepted is not an example which every-one ought to follow. The world is made up almost entirely oftwo sorts of minds to which such a course of action is whollyunsuitable. First, there are those who, believing themselvescleverer than they are, cannot stop themselves jumping toconclusions, and do not have enough patience to govern theirthoughts in an orderly way, with the result that once they haveallowed themselves to doubt accepted principles and strayfrom the common path, they would never be able to keep tothe road that one must take to proceed in the right direction,and would remain lost all their lives. Second, there are thosewho, having enough sense or modesty to realize that they areless capable of distinguishing the true from the false thancertain others by whom they could be guided, must contentthemselves with following the opinions of these others ratherthan seeking better ones from themselves.*

As for myself, I would perhaps have been in this second

category if I had only had one teacher, or if I had not knownabout the differences of opinion that have always existedamong the most learned. But having already discovered atschool that there is no opinion so bizarre and incredible thathas not been uttered by some philosopher or other,* and hav-ing come later in the course of my travels to the realization thatall those who have opinions that are diametrically opposed toours are not on that account barbarians or savages, but thatamong their number there are many who make use of theirreason as much or more than we do; and having considered howa given man with a given mind, brought up since childhood

among the French or the Germans, develops differently fromthe way he would if he had always lived among the Chineseor among cannibals, and how even down to our fashionof dress, the very thing that pleased us ten years ago andmay perhaps please us in ten years’ time at present seemsoutlandish and ridiculous to our eyes (this is because we aremuch more swayed by custom and example than any certainknowledge; and yet the majority view* is of no value as proof oftruths which are difficult to discover, because they are muchmore likely to be discovered by one man by himself than by awhole people); for all these reasons, I could not choose any oneperson whose opinions struck me as preferable to those ofothers, and I found myself forced, as it were, to provide formyself my own guidance.

But like a man walking by himself in the dark, I took thedecision to go so slowly and to exercise such caution in every-

thing that even if I made very little progress, I would at least besure not to fall. I did not even wish to begin by rejecting abso-lutely all the opinions that might have slipped into my mindwithout having been introduced there by reason, until I hadfirst spent enough time planning the work I was undertakingand searching for the true method of arriving at the knowledgeof everything that my mind was capable of grasping.

In earlier years I had made some study of logic in thephilosophy course, and of geometrical analysis and algebra inmathematics, three arts or branches of knowledge that seemeddestined to contribute to my plan. But, on examining them, Inoted, in the case of logic, that its syllogisms and most of itsother techniques are employed more to explain things to otherpeople that one knows already or even, as in the art of Lull, tospeak injudiciously about those of which one is ignorant, thanto learn anything new.* And although logic really does containmany very true and excellent precepts, there are so manyothers mixed in with them that are either harmful or superflu-ous, that it is almost as difficult to separate the former from thelatter as it is to extract a statue of Diana or Minerva from a

rough block of marble.* As for ancient geometrical analysisand modern algebra, even apart from the fact that they dealonly in highly abstract matters that seem to have no practicalapplication, the former is so closely tied to the consideration offigures that it is unable to exercise the intellect without greatly

tiring the imagination, while in the latter case one is so much aslave to certain rules and symbols that it has been turned into aconfused and obscure art that bewilders the mind instead ofbeing a form of knowledge that cultivates it.* This was why Ithought that another method had to be found which retainedthe advantages of all three but was free from their defects. Andjust as a great number of laws is often a pretext for wrong-doing, with the result that a state is much better governedwhen, having only a few, they are strictly observed; so also Icame to believe that in the place of the great number of pre-cepts that go to make up logic, the following four would besufficient for my purposes, provided that I took a firm andunshakeable decision never once to depart from them.

The first was never to accept anything as true that I did notincontrovertibly know to be so; that is to say, carefully to avoidboth prejudice and premature conclusions; and to includenothing in my judgements other than that which presenteditself to my mind so clearly and distinctly, that I would have nooccasion to doubt it.*

The second was to divide all the difficulties underexamination into as many parts as possible, and as many aswere required to solve them in the best way.

The third was to conduct my thoughts in a given order,beginning with the simplest and most easily understoodobjects, and gradually ascending, as it were step by step, to theknowledge of the most complex; and positing* an order even onthose which do not have a natural order of precedence.*

The last was to undertake such complete enumerations andsuch general surveys that I would be sure to have left nothingout.*

The long chains of reasonings, every one simple and easy,

which geometers habitually employ to reach their mostdifficult proofs had given me cause to suppose that all thosethings which fall within the domain of human understandingfollow on from each other in the same way, and that as longas one stops oneself taking anything to be true that is not trueand sticks to the right order so as to deduce one thing fromanother, there can be nothing so remote that one cannot even-tually reach it, nor so hidden that one cannot discover it.* AndI had little difficulty in determining those with which it wasnecessary to begin, for I already knew that I had to begin withthe simplest and the easiest to understand; and consideringthat of all those who had up to now sought truth in the sphereof human knowledge, only mathematicians have been able todiscover any proofs, that is, any certain and incontrovertiblearguments, I did not doubt that I should begin as they haddone. Nor did I expect any other usefulness from this, than toaccustom my mind to nourish itself on truths and reject falsereasonings. Yet I did not, for all that, intend to study all thoseparticular branches of knowledge which habitually go underthe name of mathematics;* I saw that, although their objects

were different, they nevertheless all concurred insofar as theyonly took into consideration the different relations or propor-tions to be found among these objects, and I came to think thatit was best for me to examine only these proportions in gen-eral,* without supposing their existence except in those areas ofenquiry which would serve to make my knowledge of themeasier; and moreover, not to restrict them to those areas, inorder to be better able to apply them thereafter to everythingelse to which they might be applied. Then, having notedthat, in order to know them, I would sometimes need to thinkabout them separately, and sometimes only bear them inmind, or consider many together, I came to the view that, inorder to consider these proportions best separately, I had tosuppose them to hold between lines, because I found nothingsimpler nor more capable of being distinctly represented tomy imagination* and to my senses. But for the purpose of

retaining them in my memory, or grasping several together, itwas necessary for me to designate them by the briefest possiblesymbols;* by this means I would borrow what was best fromgeometrical analysis and algebra, and would correct all thedefects of the one by the other.

And indeed, I venture to claim that the scrupulousobservance of the few precepts I had chosen gave me such easein unravelling all the questions covered by these two branchesof knowledge that in the two or three months I spent investi-gating them,* having begun with the simplest and mostgeneral (every truth that I discovered being a rule that I used

afterwards to find others), not only did I solve some which Ihad earlier judged very difficult, but it also seemed to me,towards the end of this period, that I was able to determine,even in respect of those questions which I had not solved, bywhat means and to what extent it was possible to solve them.In claiming this I will appear perhaps less conceited to you ifyou consider that, as there is only one truth of any one thing,whoever finds it knows as much as can be known about it, andthat, for example, a child trained in arithmetic who does a sumaccording to the rules can be quite certain of having discoveredeverything the human mind can find out about the sum inquestion. In short, the method that teaches one to follow thecorrect order and to enumerate all the factors of the objectunder examination, contains everything that confers certaintyon arithmetical rules.

But what pleased me most about this method was that,through it, I was certain in all cases to employ my reason, ifnot perfectly, then at least to the best of my ability; moreover, Ibelieved that, in practising it, my mind was gradually gettingused to conceiving of its objects more clearly and distinctly,and that not having set it to work on any particular matter, Iwas able to set myself the task of applying it just as usefully tothe problems of other branches of knowledge* as I had done tothose of algebra. Not that I ventured, for all that, to examineall the problems I might come across; for that would have been

contrary to the order prescribed by my method. But havingnoted that the principles of each branch of knowledge must ofnecessity all be borrowed from philosophy, in which I could

still find no certain principles, I came to think that it was firstnecessary for me to try to establish some; and that this beingthe most important thing in the world and one in which unduehaste and preconceptions were most to be feared, I thoughtthat I ought not to attempt to carry this task through to com-pletion until I had reached a much more mature age than thetwenty-three years I then was, and until I had spent consider-able time in preparing myself for the task, as much by rootingout of my mind all the false opinions I had accepted up tothen, as by amassing a large number of experiences to serveafterwards as the matter of my reasoning, and by continuallypractising my chosen method in order to strengthen mygrasp of it.

PART THREE

Finally, just as it is not enough, before beginning to rebuild thehouse in which one lives, to do no more than demolish it, makeprovision for materials and architects, or become oneselftrained as an architect, or even to have carefully drawn up theplans, but one must also provide oneself with another house inwhich one may be comfortably lodged while work is in pro-gress; so also, in order not to remain indecisive in my actionswhile my reason was forcing me to be so in my judgements,and to carry on living from then on as happily as I could, Iformed a provisional moral code* for myself consisting in onlythree or four maxims, which I should like to share with you.

The first was to obey the laws and customs of my country,*

and to adhere to the religion in which God by His grace hadme instructed from my childhood, and to govern myself ineverything else according to the most moderate and leastextreme opinions, being those commonly received among thewisest of those with whom I should have to live. For, havingbegun already to discount my own opinions because I wishedto subject them all to rigorous examination, I was certain that Icould do no better than to follow those of the wisest. Andalthough there may be as many wise people among the Persiansand the Chinese as among ourselves, it seemed to me that themost useful thing to do would be to regulate my conduct bythat of the people among whom I was to live; and that for meto know what their opinions really were, I had to take note ofwhat they did rather than what they said,* not only because inthe present corrupt state of our morals few people are willingto declare everything they believe, but also because some donot even know what they believe; for the mental act by whichwe believe something, being different from that act by whichwe know that we believe it,* often results in one act beingpresent without the other. And I chose only the most moderate

among many opinions which were equally widely received, asmuch because these are always easiest to practise and likely tobe the best (excesses all being usually bad) as to wander less farfrom the true path in case I should be wrong, and that havingfollowed one extreme, it transpired that I should have followedthe other. And in particular, I placed in the category of these

excesses all personal commitments by which one relinquishessome of one’s freedom. Not that I disapprove of the laws that,in order to counteract the inconsistency of those who areweak-minded, permit men to make verbal undertakings orcontracts which bind them not to break them (in cases wherethey have some worthy plan, or even, to guarantee the securityof commerce, some plan which is no more than morallyindifferent); but, because I saw nothing in this world whichremained always in the same state, and because in my own caseI set myself the task of gradually perfecting my judgementsand not of making them worse, I would have seen myself assinning against good sense if, having once approved of some-thing, I should have found myself obliged to take it to be goodlater on, when it might have ceased to be so, or I might haveceased to consider it so.

My second maxim was to be as firm and resolute in myactions as I could, and to follow no less constantly the mostdoubtful opinions, once I had opted for them, than I wouldhave if they had been the most certain ones.* In this I imitatedthose travellers who, finding themselves lost in a forest, mustnot wander in circles first to one side then to the other, and stillless stop in one place, but have to walk as straight as possible inone direction, and not alter course for weak reasons, even if itmight only have been chance which had led them to settle onthe direction they had chosen; for by this means, even if theydo not end up precisely where they want to be, they will even-tually reach somewhere where they will most likely be better

off than the middle of a forest. And, in the same way, as in lifewe must often act without delay, it is a very certain truth thatwhen it is not in our power to determine which the truest

opinions are, we should follow those which are most likely tobe true, and even though we might see no more probability* insome rather than others, we must nevertheless opt for one set,and thereafter consider them not as being doubtful, insofar asthey relate to the practice of life, but as altogether true andcertain, because the reasoning that led us to opt for them istrue and certain. This maxim was able from then on to free mefrom all the regret and remorse that usually troubles the con-sciences of weak and vacillating minds, who are inconsistentand allow themselves to follow certain practices as though theywere good, that they later judge to be bad.

My third maxim was to endeavour always to master myselfrather than fortune, to try to change my desires rather than tochange the order of the world, and in general to settle for thebelief that there is nothing entirely in our power except ourthoughts, and after we have tried, in respect of things externalto us, to do our best, everything in which we do not succeed isabsolutely impossible as far as we are concerned.* This aloneseemed to me to be sufficient to prevent me from desiringanything in future which I could not obtain, and thereby tomake me content. For as our will is naturally inclined to desire

only those things which our intellect represents to it as pos-sible in some way, it is certain that if we consider all externalgoods as being equally beyond our power, we shall not feel anymore regret at failing to obtain those which seem to be ourbirthright when deprived of them through no fault of our own,than we shall for not possessing the kingdoms of China andMexico; and by making a virtue out of necessity, as the sayinggoes, we shall no more desire to be healthy when we are ill orfree when we are in prison, than we do now to have bodiesmade of matter as incorruptible as diamonds or wings to allowus to fly like birds. But I admit that it takes long practice andreiterated periods of meditation* to make oneself used to see-ing things from this angle; and I believe that it is principally inthis that lay the secret of those philosophers who were able inearlier times to escape the tyranny of fortune and, in spite of

suffering and poverty, to rival their gods in happiness.* Forthrough constant reflection on the limits laid upon them bynature, they convinced themselves so completely that nothingwas in their power other than their thoughts, that this convic-tion alone was sufficient to prevent them from having anydesire for anything else; and they controlled their thoughts soeffectively that they thereby believed themselves with somereason to be richer, more powerful, freer, and happier than anyother men who, not having this philosophy, never have this

control over their desires, however favoured by nature andfortune they may be.*

Finally, as a conclusion to this moral code, I decided toreview the various occupations that men have in this life, inorder to try to select the best one. Without wishing to passjudgement on the occupations of others, I came to the viewthat I could do no better than to continue in the one in which Ifound myself, that is to say, to devote my life to the cultivationof my reason and make such progress as I could in the know-ledge of the truth following the method I had prescribed formyself. I had experienced such great joy since I began toemploy this method that I did not believe that any sweeter ormore innocent pleasures were to be had in this life; and as Idiscovered daily by its means a number of truths that seemedto me very important and generally unknown to other men,the satisfaction that I obtained from it filled my mind to such adegree that nothing else mattered to me. Besides, the threeforegoing maxims were based only on the plan I had to con-tinue to seek knowledge; for since God has given each of us aninner light* to distinguish the true from the false, I would nothave believed for one moment that I should content myselfwith the opinions of others, if I had not intended in due courseto use my own judgement to examine them; and I could nothave avoided having scruples about following them, if I hadnot hoped thereby to seize every opportunity to find betterones, in case there were any. Finally, I should not have known

how to limit my desires or achieve happiness, if I had not

followed a path by which I thought I was sure to acquire all theknowledge of which I was capable, and, by the same means, allthe true goods that it would ever be in my power to obtain; andseeing that our will tends to pursue or shun only what ourintellect represents to it as good or bad, it is sufficient to makea sound judgement in order to act well, and to judge as well aswe can in order to do our best;* that is to say, to acquire all thevirtues and with them all the other goods we are capable ofacquiring. And when we are certain that this state of affairsexists, we cannot fail to be happy.

Once I had established these maxims, and set them aside inmy mind with the truths of the faith which have always heldfirst place in my beliefs, I took the decision that, as far as therest of my opinions were concerned, I could freely undertaketo rid myself of them. And seeing that I expected to be betterable to complete this task in the company of others than byremaining shut any longer in the stove-heated room in which Ihad had all these thoughts, I set out on my travels again beforewinter was over. And through all the next nine years* I didnothing but wander through the world, trying to be a spectatorrather than an actor in all the dramas that are played out onthat stage; and, reflecting particularly in each matter on whatmight make it suspect and give occasion for error, I proceededto eradicate from my mind all the mistakes that might earlier

have crept into it. In doing this, I was not copying those scep-tics who doubt for doubting’s sake, and pretend to be alwaysunable to reach a decision;* for, on the contrary, the aim of mywhole plan was to reach certainty and reject shifting ground inthe search for rock and clay. And in this, it seems to me, Isucceeded reasonably well, seeing that, in trying to expose thefalsity or uncertainty of the propositions that I was investigat-ing not by weak conjectures but by clear and certain reasoning,I found none so doubtful that I could not draw some reason-ably certain conclusion from it, even if the conclusion was nomore than that the proposition in question contained nothingof certainty. And just as, in demolishing an old building, one

usually preserves the debris in order to use it in constructing anew one; so also, in destroying all those of my opinions which Ijudged to be ill-founded, I made various observations andaccumulated many experiences* which have been of use to mesubsequently in establishing more certain opinions. What ismore, I continued to practise the method I had prescribed formyself, for, besides taking care generally to conduct all mythoughts according to these rules, I occasionally set aside a fewhours which I spent applying it to difficulties in mathematics,or even to others which I could more or less translate intomathematical terms by removing from them all the principlesof the other branches of knowledge which I did not find solidenough; you will see I have done this to many problems thatare dealt with in this volume.* And so, while apparently living

in the same way as those who, having no occupation other thanleading a blameless and agreeable life, take care to keep theirpleasures free from vices and who, in order to enjoy theirleisure without becoming bored, engage in all those pastimesthat are honourable, I never stopped pursuing my plan andmaking progress in the knowledge of truth, perhaps more thanif I had done nothing else than read books* and spend time inthe company of men of letters.

However, those nine years passed by before I had reachedany decision about the questions that are often debated amongthe learned, or had begun to look for the foundations of anyphilosophy which might be more certain than that which iscommonly received. And the example of the many excellentminds who, having embarked on this project before me, didnot appear to have succeeded,* led me to see it as so difficultthat I would perhaps not have dared to undertake the task soearly if I had not learned that some people were alreadyspreading the rumour that I had completed it. I cannot say onwhat they based this opinion. If I have done anything to con-tribute to it by what I have said in public, it must have been byowning up to what I did not know with greater freedom thanis usual among those who have undertaken some study, and

perhaps also by revealing the reasons that I had to doubt muchthat others take to be certain, rather than by boasting of anypositive knowledge. But having enough self-esteem not to wishto be taken for other than I was, I came to think that it wasnecessary for me to try by every possible means to make myselfworthy of the reputation I was being given. And it is now just

eight years since this desire made me decide to move awayfrom all the places where I might have acquaintances and toretire here,* in a country in which the long period of war hasestablished such good discipline that the armies that are main-tained here seem only to serve to ensure that people enjoy thefruits of peace with correspondingly greater security, andwhere amid a teeming, active, great people that shows moreinterest in its own affairs than curiosity for those of others,I have been able to live as solitary and as retiring a life as Iwould in the most remote of deserts, while lacking none of thecomforts found in the most populous cities.*

PART FOUR

I do not know whether I am bound to tell you about the firstmeditations that I engaged in there, for they are so meta-physical and recondite that they may not be to everyone’staste. And yet, to make it possible to judge whether the foun-dations I have laid are firm enough, I find myself in a wayforced to speak about them. As has already been said, I hadlong since observed that, as far as morals are concerned, it isnecessary sometimes to follow opinions which one knows to bevery unsure as if they were indubitable; but because I wishedat that time to concentrate on the pursuit of truth, I came tothink that I should do the exact opposite and reject as com-pletely false everything in which I could detect the least doubt,in order to see if anything thereafter remained in my belief thatwas completely indubitable. And so, because our senses some-

times deceive us, I decided to suppose that nothing was such asthey lead us to imagine it to be.* And because there are menwho make mistakes in reasoning, even about the simplestelements of geometry, and commit logical fallacies, I judgedthat I was as prone to error as anyone else, and I rejected asfalse all the reasoning I had hitherto accepted as valid proof.*Finally, considering that all the same thoughts which we havewhile awake can come to us while asleep without any one ofthem then being true, I resolved to pretend that everythingthat had ever entered my head was no more true than theillusions of my dreams. But immediately afterwards I notedthat, while I was trying to think of all things being false in thisway, it was necessarily the case that I, who was thinking them,had to be something; and observing this truth: I am thinkingtherefore I exist,* was so secure and certain* that it could not beshaken by any of the most extravagant suppositions of thesceptics, I judged that I could accept it without scruple, as thefirst principle of the philosophy I was seeking.*

Next, examining attentively what I was, I saw that I couldpretend that I had no body and that there was no world orplace for me to be in, but that I could not for all that pretendthat I did not exist; on the contrary, from the very fact that Ithought of doubting the truth of other things, it followedincontrovertibly and certainly that I myself existed, whereas, ifI had merely ceased thinking, I would have no reason to believe

that I existed, even if everything else I had ever imagined hadbeen true. I thereby concluded that I was a substance whosewhole essence or nature resides only in thinking, and which, inorder to exist, has no need of place and is not dependent onany material thing. Accordingly this ‘I’, that is to say, the Soul*by which I am what I am, is entirely distinct from the body andis even easier to know than the body; and would not stop beingeverything it is, even if the body were not to exist.

After this, I came to think in general about what is requiredfor a proposition to be true and certain; for since I had justfound one such proposition, I thought that I ought also toknow in what this certainty consists. And having observed thatthere was nothing in this proposition, I am thinking therefore Iexist, which makes me sure that I am telling the truth, exceptthat I can see very clearly that, in order to think, one has toexist, I concluded that I could take it to be a general rule thatthings we conceive of very clearly and distinctly are all true,but that there is some difficulty in being able to identify thosewhich we conceive of distinctly.

As a result of which, as I thought about the fact that I wasdoubting and that consequently my being was not altogetherperfect (for I saw clearly that it was a greater perfection toknow than to doubt), I decided to look for the source fromwhich I had learned to think of something more perfect than Iwas myself, and I came to the incontrovertible realization thatthis must be from some nature that was in fact more perfect.

As for the thoughts I had about many other things outsidemyself, such as the heavens, the earth, light, heat, and numer-ous others, I had no such difficulty in knowing where they

came from, because, seeing nothing in them which seemed tomake them superior to myself, I could believe that if they weretrue, they depended on my nature in so far as it containedsome perfection; and if they were not true, I held them fromnothing, that is to say, that they were in me because I waslacking something.* But this could not be true of the idea of abeing more perfect than mine; for it was manifestly impossiblethat I should hold this from nothing; and because it is no lesscontradictory that the more perfect should proceed from anddepend on the less perfect than it is that something shouldproceed from nothing,* I could not hold it from myself either.So that there remained only the possibility that it had been putinto me by a nature which was truly more perfect than mine,and one which even had in itself all the perfections of which Icould have any idea, that is to say, in a word, which was God.*To which thought I added that, because I knew some perfec-tions that I did not myself have, I was not the only being whoexisted (I shall here freely employ, with your permission, somescholastic terminology), but that of necessity there must besome other, more perfect being upon whom I depended andfrom whom I had acquired all that I possessed. For if I hadbeen the sole being and had been independent of every otherbeing so as to have, of myself, that small degree of participation

in the perfection which I shared with the perfect being, I couldhave been able to have of myself, by the same reason, all theremaining perfection that I knew myself to lack,* and so bemyself infinite, eternal, unchanging, omniscient, in a word, tohave all the perfections which I could observe in God. For, byfollowing this line of reasoning, for me to know the nature ofGod in so far as my own nature permitted it, I only had toconsider, in respect of each thing of which I found in myselfsome idea, whether it was a perfection to possess it; and I wascertain that none of those things which manifested any imper-fection was in Him, but that all the others were. In this way Icould see that doubt, inconstancy, sadness, and such thingscould not be in Him, given that I would have been myself very

glad to be free of them. Besides this, I had ideas of manycorporeal things in the realm of the sensory; for even if I wereto suppose that I was dreaming and that everything that I saw orimagined was false, I nevertheless could not deny that the ideaswere really in my thought; but because I had already recog-nized in my own case that the nature of the intellect is distinctfrom the nature of the body, and considering that all com-position is evidence of dependence, and that dependence ismanifestly a defect,* I concluded that it could not be one ofGod’s perfections to be composed of these two natures, andthat, as a consequence, He was not so composed; but that, ifthere were in the world any bodies or other intelligences*or other natures which were not wholly perfect, their being

must depend on His power, in such a way that they could notcontinue to subsist for a single moment without Him.*

I decided after that to look for other truths; I called to mindthe object of study of geometers, which I conceived of as acontinuous body or a space indefinitely extended in length,breadth, and height or depth, divisible into different partswhich could have various figures and sizes, and be moved ortransposed in all sorts of ways, for geometers posit all that to betheir object of study. I ran through some of their simplerproofs, and observed that the great certainty which everyoneattributes to them is based only on the fact that they are con-ceived of as incontrovertible, following the rule that I have justgiven. I noted also that there was absolutely nothing in themwhich made me certain of the existence of their object. Thus,for example, I grasped clearly that, supposing a triangle to begiven, it was necessary that its three angles were equal to tworight angles; yet for all that, I saw nothing in this which mademe certain that a single triangle existed in the world. Whereas,going back to the idea I had had of a perfect being, I found thatexistence was part of that idea, in the same way, or even moreincontrovertibly so, that it is intrinsic to the idea of a trianglethat its three angles equal two right angles, or to that of asphere that all its parts are equidistant from its centre; and

that, in consequence, it is at least as certain as any geometricproof that God, who is that perfect being, is or exists.*

But what convinces many people that there is a problem in

knowing Him and even of knowing what their soul is, is thatthey never raise their mind above the realm of sensory thingsand are so used not to think of anything except by imagining it,which is a mode of thinking peculiar to material objects, thateverything which seems unimaginable seems to them unintel-ligible.* This is clear enough from the fact that even scholasticphilosophers hold as a maxim that there is nothing in theintellect which has not previously been in the senses,* in which,however, it is certain that the ideas of God and the soul havenever been. It seems to me that people who wish to use theirimagination in order to understand these ideas are doing thesame as if, in order to hear sounds or smell smells, they tried touse their eyes. Except that there is this further difference, thatthe sense of sight no more confirms to us the reality of thingsthan that of smell or hearing, whereas neither our imaginationnor our senses could ever confirm the existence of anything, ifour intellect did not play its part.

Finally, if there are still people who are not sufficientlyconvinced of the existence of God and of their soul by thearguments I have adduced, I would have them know thateverything else of which they think they can be more certain,such as their having a body, or there being stars and an earthand suchlike, is in fact less certain. For although for all prac-tical purposes we possess an assurance* of these things suchthat it seems that no one can doubt their existence without

being wilfully eccentric, nevertheless, where metaphysical cer-tainty is in question, no one can deny, short of being irrational,that there are sufficient grounds for not being absolutely cer-tain, as when we note that while we are asleep we can in thesame way imagine having another body, or seeing other starsand another earth, without this being in fact the case. For howdo we know that the thoughts that come to us in dreams areany more false than the others, seeing that they are often no

less vivid and clear? However much the best minds choose toinvestigate this matter, I do not believe that they will be able tofurnish any argument which is sufficient to remove this doubt,unless they presuppose the existence of God. For, in the firstplace, even the rule which I stated above that I held––namely,that the things that we conceive very clearly and very distinctlyare all true––is only certain because God is or exists, becauseHe is a perfect being, and because everything that is in uscomes from Him.* From which it follows that our ideas ornotions, being real things which moreover come from God,insofar as they are clear and distinct, cannot thereby but betrue. So that if we quite often have ideas containing somefalsity, these can only be those which contain something insome way confused or obscure, because in this they participatein nothingness, that is to say, that they are in us in this con-fused form because we are not wholly perfect.* And it is mani-fest that there is no less contradiction in the proposition thatfalsity and imperfection as such come from God, than there is

in the proposition that truth or perfection come from nothing-ness. But if we did not know that everything that is real andtrue in us comes from a perfect and infinite being, then, nomatter how clear and distinct our ideas were, we would have noreason to be assured that they possess the perfection of beingtrue.

Now once the knowledge of God and of the soul has madeus certain of this rule, it is a simple matter to determine thatthe things we imagine in dreams should in no way make usdoubt the truth of the thoughts we have while awake. For evenif one should happen while sleeping to have some very distinctidea, as for example, in the case of a geometer discoveringsome new proof, the fact that he was asleep would not preventit being true. And as for the most common error of ourdreams, which consists in their representing various things tous in the same way as our external senses, it does not matterthat it gives us occasion to distrust the truth of such ideas,because our senses could also quite often mislead us without

our being asleep;* as when those who suffer from jaundice seeeverything as yellow, or when stars or other very distant bodiesappear to us much smaller than they are. For after all, whetherwe are awake or asleep, we ought never to let ourselves beconvinced except on the evidence of our reason. And it is to benoted that I say ‘our reason’, and not ‘our imagination’ or ‘oursenses’. For although we see the sun very clearly, we should

not on that account judge that it is only as large as we see it;and we can well imagine the head of a lion grafted onto thebody of a goat, without having necessarily to conclude fromthis that a chimera exists in the world;* for reason does notdictate to us that what we see or imagine in this way is true.But it does certainly dictate that all our ideas or notions musthave some foundation in truth; for it would not otherwise bepossible that God, who is all-perfect and altogether true,should have placed them in us unless it were so. Our processesof reasoning are never so clear or so complete while we areasleep as when we are awake (even though our imaginings insleep are sometimes just as vivid and distinct); so reason tellsus also that as our thoughts cannot all be true because we arenot wholly perfect, what truth there is in them must infallibly*be found in those we have while awake rather than in those wehave in our dreams.

PART FIVE

I would gladly go on and reveal the whole chain of the othertruths that I deduced from these first ones. But in order toachieve this end, it would be necessary here for me to broachseveral questions that are controversial among learned menwith whom I do not wish to fall out, and so I believe it wouldbe best for me to abstain from doing this, and state only inbroad terms what these questions are, in order to leave wiserheads to judge whether it would be profitable for the public tobe informed about them in greater detail. I have always stuck

to the decision I took not to posit any principle other than thatwhich I have just used to prove the existence of God and of thesoul, and not to take anything to be true which did not seem tome clearer and more certain than the proofs of geometers hadpreviously seemed. And yet I venture to say that I have notonly found the way to satisfy myself in a short space of timeabout all the principal difficulties usually discussed in phil-osophy, but I have also come to see certain laws which God hasestablished in such a way in nature, and of which He hasimprinted notions of such a kind in our souls, that after suf-ficient reflection on them, we cannot doubt that they arestrictly observed in everything that exists or occurs in theworld. Moreover, by considering what follows from these laws,it seems to me that I have discovered many truths more usefuland important than anything I had hitherto learned or evenhoped to learn.

But since I tried to explain the most important of these in atreatise which certain considerations prevent me from publish-ing,* I cannot let them be known better than by saying herebriefly what the treatise contains. Before I started writing it, Ihad intended to include in it everything that I believed I knewabout the nature of material things. But just like those painterswho, being unable to represent equally in a flat picture all the

various faces of a solid body, choose only one of the principalones which they place in the light, leaving the others inshadow, representing them to the extent that one can see them

when one looks at the chosen face; so also, fearing that I couldnot put everything that I had in my mind in my discourse, Iundertook only to reveal fully my conception of light; there-after, I took the opportunity of adding something about thesun and the fixed stars, because light proceeds almost whollyfrom them; something about the heavens, because they trans-mit it; something about the planets, the comets, and the earth,because they reflect it; and in particular something about ter-restrial bodies, because they are either coloured, or transpar-ent, or luminous; and finally something about man, because heis the spectator of all this. And in order to remove these thingsfrom the spotlight and to be able to say more freely what Ithought about them without being obliged either to confirm orrefute the opinions of learned men, I decided to leave thisearth wholly for them to discuss, and to speak only of whatwould happen in a new world, if God were now to createenough matter to compose it somewhere in imaginary space,*and if He were to agitate the different parts of this matter indiverse and indiscriminate ways so as to create from it a chaosas confused as any poet could possibly imagine; and that Hethen did no more than sustain nature in His usual manner,leaving it to act according to the laws He has established. So Ifirst described this matter and tried to represent it so that thereis nothing in the world, I think, clearer and more intelligible,except what has just been said of God and the soul; for I evenmade the explicit supposition expressly that it contained none

of the forms or qualities* which are discussed by scholasticphilosophers, and that it had nothing in general that was not sonaturally known to our souls that we could not even pretend tobe ignorant of it. Further, I revealed what were the laws ofnature; and basing my reasoning on no other principle than theinfinite perfections of God, I set out to prove all those lawsabout which one might have had some doubt, and to show that

they are such that even if God had created many worlds, therecould be not be any in which they could have failed to beobserved. After that, I demonstrated how the greater part ofthe matter of this chaos must, in consequence of these laws, bedisposed and arranged in a way which made it similar to theheavens above us; how, at the same time, some of its parts hadto compose an earth, some others planets and comets, yetothers a sun and fixed stars. And here, enlarging on the subjectof light,* I explained in detail the nature of the light to be foundin the sun and the heavenly bodies, the way it crossed in aninstant the immense expanses of the heavens, and how it wasreflected from the planets and the comets towards the earth. Iadded also many things about the substance, position, motions,and all the various qualities of these heavens and stars; so that Ithought I had said enough to show that nothing was to beobserved in those of our world which must not or at least couldnot appear wholly similar to the world I was describing. Next,

I came to speak about the earth in particular, and to discusshow, although I had made the explicit supposition that Godconferred no weight* on the matter of which it was composed,all its parts nonetheless tended exactly towards its centre; how,there being water and air on its surface, the dispositions of theheavens and the heavenly bodies (principally the moon) mustcause tidal movement similar in every circumstance to thatwhich we observe in our seas; and together with all this, acertain current, as much of the water as of the air, from east towest, such as we find here in our tropics; how mountains, seas,springs, and rivers could naturally form themselves, metalsappear in the mines, plants grow in the countryside, and ingeneral, how all the bodies that are called mixed or composedcome into being there. And among other things, because apartfrom the heavenly bodies I knew of nothing in the world whichproduces light apart from fire, I set out to explain very clearlyeverything which pertains to its nature, how it comes aboutand how it sustains itself; how there is sometimes only heatwithout light and sometimes only light without heat; how it

can introduce different colours and various other qualities intodifferent bodies; how it melts some things and hardens others,how it can consume nearly all of them or turn them into ashesand smoke; and finally, how it can form glass from these ashes,by nothing other than the power of its action. I took particularpleasure in describing this, for the transmutation of ashes into

glass seemed to me as remarkable a transformation as any thatoccurs in nature.

Yet I did not wish to infer from all this that our world wascreated in the way I suggested; for it is much more plausiblethat from the beginning God made it as it was to be. But it iscertain (and this is an opinion widely held among theologians)that the act by which He conserves the world is the same asthat by which He created it.* So, even if He might not havegiven it any other form at the beginning than chaos, providedthat He established the laws of nature and gave nature the helpto act as it usually acts, we may believe, without casting doubtupon the miracle of creation,* that all purely material thingswould have been able, in time, to make themselves into whatwe see them to be at present in this way alone. And theirnature is much easier to conceive of, when we think of theirgradual emergence in this way, than when we only considerthem in their final form.

From the description of inanimate bodies and plants Ipassed to that of animals, and in particular to that of men. Butbecause I did not yet know enough to speak about it in thesame way as I did about the rest, that is to say, by provingeffects from causes, and showing from what elements and bywhat process nature must produce them, I contented myselfwith the supposition that God formed the body of a man,exactly like our own both in the external shape of his members

and in the internal configuration of his organs, constitutinghim of no other matter than that which I had alreadydescribed, and without placing in him in the beginning arational soul, or anything else which could function as a vegeta-tive or sensitive soul,* but merely kindling in his heart one of

those fires without light which I had already explained andwhose nature I conceived of as no different from the fire thatheats hay when it has been stored before it was dry, or makesnew wine rise in temperature, when it is left to ferment onthe lees. For, in investigating the functions that could as aconsequence be in this body, I found precisely all those whichcan be in us without our thinking of them, and to which oursoul, that is to say, that part of us distinct from the bodywhose sole nature, as has been said above, is to think, contrib-utes nothing; these functions are the same as those in whichirrational animals may be said to resemble us. But I wasunable to find in this body any of those functions which,being dependent on thought, are the only ones that belong tous as human beings, whereas I found them all there sub-sequently, once I had supposed that God created a rationalsoul and that He joined it to this body in a particular waywhich I described.

But so that one may see how I dealt with this matter, I wishto give here the explanation of the movement of the heart andthe arteries, from which, being the first and most generalmovement that is observed in animals, readers will determinemore easily what they must think about all the others. And so

that they might have less difficulty understanding what I shallsay about it, I should like those who are unversed in anatomyto take the trouble, before reading this, of having the heart of alarge animal with lungs dissected before their eyes (for it is inall respects sufficiently like that of a man) and of having its twochambers or cavities pointed out to them. First, the one whichis on the right side, to which two very wide tubes are con-nected; that is, the vena cava, which is the principal receptacleof blood and, as it were, the trunk of the tree of which all otherveins in the body are the branches; and the vena arteriosa,which has been ill-named, being in fact an artery, which has itsorigin in the heart, and having emerged from it, divides intomany branches that spread throughout the lungs. Next, thecavity on the left side, to which two tubes are connected in the

same way, which are as wide or wider than the preceding ones;that is, the arteria venosa, which has also been ill-named,because it is nothing other than a vein, which comes from thelungs where it is divided into many branches, intertwined withthose of the vena arteriosa, and those with the tube called thetrachea through which the air we breathe enters; and the aortawhich, coming out from the heart, sends its branches through-out the body. I should also like my readers to be shown care-fully the eleven small membranes which, like so many littledoors, open and close the four apertures which are in these twocavities; namely, three at the entrance to the vena cava, where

they are so disposed that they cannot prevent the blood itcontains from flowing into the right cavity of the heart and yetat the same time completely stop the blood from leaving it;three at the entrance to the vena arteriosa, which, being dis-posed in the opposite way, allow the blood in that cavity to passinto the lungs, but stop the blood in the lungs from returningto the heart; and two others at the entrance to the arteriavenosa, which allow in the same way the blood from the lungsto flow towards the left cavity of the heart, but prevent it fromreturning; and three at the entrance to the aorta, which allowblood to leave the heart but stop it returning. And there is noneed to look for any other cause for the number of these mem-branes other than that the aperture of the arteria venosa, beingoval in shape on account of its location, can easily be closedwith two of them, whereas the others, being round, can moreeasily be closed with three. Moreover, I would wish my readersto have pointed out to them that the aorta and the vena arte-riosa are of a much harder and firmer texture than the arteriavenosa and the vena cava, and that these latter two widen outbefore entering the heart to form two pouches, as it were,called the auricles of the heart, which are composed of similarsubstance to the heart itself. They will observe also that thereis always more heat in the heart than in any other part of thebody; and finally, that this heat is able to cause a drop of bloodentering its cavities to swell up at once and to dilate, in the

same way that all liquids do when they are allowed to fall dropby drop into a very hot vessel.

I have no need after this to say more to explain the move-ment of the heart, except that when its cavities are not full ofblood, blood necessarily flows from the vena cava into the rightcavity and from the arteria venosa into the left; for these twovessels are always full of blood, and their apertures, whichopen into the heart, cannot then be blocked; but, as soon astwo drops of blood have entered the heart in this way, one intoeach cavity, these drops (which must very great, since the aper-tures by which they enter are very wide and the vessels fromwhich they come are full of blood) rarify and dilate because ofthe heat they find there. In this way they cause the whole heartto swell, and they push shut the five little doors which are atthe entrances of the two vessels from which they flowed, thuspreventing any more blood coming down into the heart. Con-tinuing to become more and more rarified, the drops of bloodpush open the six other little doors which are at the entrancesof the two other vessels through which the blood leaves theheart, causing in this way all the branches of the vena arteriosaand the aorta to swell at more or less the same time as theheart.* Immediately afterwards the heart contracts, as do thesearteries also, because the blood that has entered them hascooled, and their six little doors shut again; and the five doorsof the vena cava and the arteria venosa open again and allowtwo new quantities of blood to pass through, which immedi-

ately cause the heart and the arteries to swell up as before. Andbecause the blood that enters the heart in this way, passesthrough the two pouches which are called auricles, it followsfrom this that their movement is the opposite of the heart’s,and that they contract when the heart swells. Finally, so thatthose who do not know the force of mathematical proof andare not used to distinguish true reasoning from plausible reason-ing, should not venture to deny all this without examining it,I would like to point out to them that the movement I havejust explained follows necessarily from the mere disposition of

organs that one can see with the naked eye in the heart, fromthe heat which one can feel there with one’s fingers, and fromthe nature of blood which one can know from observation,in the same way as the movement of a clock follows from theforce, position, and shape of its counterweights and wheels.*

But if one asks why the blood in the veins is not all used upby flowing continually in this way into the heart, and why thearteries are not too full because all the blood which passesthrough the heart goes into them, I need only repeat theanswer already given by an English doctor, who must bepraised for having broken the ice on this subject.* He was thefirst to show that there are many small passages at the extrem-ities of the arteries through which the blood they receive fromthe heart enters the small branches of the veins, from which itimmediately goes back to the heart, so that its course is noth-ing but a perpetual circulation. He proves this very well from

the common experience of surgeons, who, having bound anarm moderately tightly above the point where they open avein, make the blood flow out more abundantly than if theyhad not bound the arm. And the opposite would happen ifthey bound the arm below, between the hand and the veinbeing opened, or if they bound it very tightly above. For it isobvious that the moderately tight ligature, while being able toprevent the blood that is already in the veins from returning tothe heart through the veins, cannot stop on that account freshblood arriving from the arteries, because they are situatedbelow the veins and their walls, being harder, are less easy tocompress; and because the blood coming from the heart tendsto flow through the arteries to the hand with greater force thanit does when returning from the hand towards the heartthrough the veins. And because the blood comes out of thearm through the opening in one of the veins, there must neces-sarily be some passages below the ligature, that is to say,towards the extremities of the arm, through which it can comefrom the arteries. He also proves very well what he says aboutthe circulation of the blood, first by certain small membranes

which are disposed at various points along the veins in such away that they do not let blood pass from the centre of the bodytowards its extremities, but only permit it to return from theextremities towards the heart; second, by the experiment thatshows that all the blood in the body can flow out of it in a veryshort space of time by a single artery when it is cut, even if it istightly bound close to the heart, and cut between the heart andthe ligature, so that there is no reason to imagine that the blood

that flows out comes from anywhere but the heart.But there are many other things which are evidence of the

fact that the true cause of this movement of the blood is as Ihave said it is. First, there is the difference to be observedbetween the blood which issues from the veins and that whichissues from the arteries; this can only be due to the fact that,being rarefied, and, as it were, distilled in passing through theheart, it is thinner, more lively, and hotter straight after leavingit (that is to say, while in the arteries), than it is shortly beforeentering the heart (that is to say, while in the veins). And if onemakes a careful observation, one will find this difference isonly clearly perceptible close to the heart and not as per-ceptible in the parts most distant from it. Next, the hardness ofthe walls of which the vena arteriosa and the aorta are com-posed indicates clearly enough that blood beats against thesemore powerfully than against the veins. And why should theleft cavity of the heart and the aorta be larger and wider thanthe right cavity and the vena arteriosa, if not because the bloodof the arteria venosa, having been in the lungs only since it leftthe heart, is thinner and becomes more easily rarefied than theblood which flows directly from the vena cava? And what canphysicians find out from taking the pulse if they did not knowthat, as the nature of blood changes, it can be rarefied by theheat of the heart to a greater or lesser degree and more or lessquickly than before? And if we examine how this heat com-municates itself to the other members of the body, must we notadmit that this happens by means of the blood which is

reheated as it passes through the heart and spreads from there

throughout the body? From which it follows that, if we removeblood from some part of the body, we remove heat by the samemeans as well, and even if the heart were as hot as a piece ofglowing iron, it would not have sufficient heat to warm up thehands and feet as it does at present, unless it continually sentnew blood to them. Then, too, we know from this that the truefunction of breathing is to bring enough fresh air into thelungs to cause the blood entering them from the right cavityinto the heart, where it has been rarefied and, as it were,changed into vapour, to thicken up and convert itself oncemore into blood, before falling back into the left cavity; if it didnot do this, it would not be fit to nourish the fire that is there.All this is confirmed by the fact that we see that animals nothaving lungs have also only one cavity in the heart, and thatunborn children, who cannot use their lungs while in theirmother’s womb, have an aperture through which blood flowsfrom the vena cava into the left cavity of the heart, and a ductby which it comes from the vena arteriosa to the aorta, withoutpassing through the lung. And then, how could digestionoccur in the stomach, if the heart did not send heat therethrough the arteries, together with some of the most fluid partsof the blood, which help to dissolve the food that we haveingested? And is it not easy to understand the action whichconverts the juice of this food into blood, if we consider thatthe blood is distilled perhaps more than one or two hundredtimes every day by passing repeatedly through the heart? Andwhat else is needed to explain nutrition and the production of

the various humours* present in the body other than to say thatthe force with which the blood passes, as it rarefies, from theheart to the extremities of the arteries, causes some of its partsto come to rest in the parts of the members in which they thenfind themselves and there take the place of other parts whichthey expel; and that, according to the position, shape, or smallsize of the pores they encounter, some parts of the blood ratherthan others flow to certain places, in the same way that we seethat sieves with different grades of mesh serve to separate

different grains from each other? And finally, the mostremarkable thing about all this is the generation of animalspirits,* which, like a very subtle* wind, or rather like a very pureand living flame, rise continually in great abundance from theheart to the brain, pass from there through the nerves into themuscles, and impart movement to all our members. We donot need to suppose any other cause to impel the most agi-tated and the most penetrating parts of the blood (and hencethe best suited to compose these spirits) to make their way tothe brain rather than anywhere else, than that the arteries thatcarry them there are those which come most directly from theheart, and that, according to the rules of mechanics (whichare the same as those of nature), when many things tend tomove together towards the same place in which there is notroom for them all (as in the case of the parts of the blood thatleave the left cavity of the heart and flow towards the brain),the weaker or less agitated must of necessity be displaced by

the stronger, which by this means reach their destination ontheir own.

I had explained all these matters in considerable detail inthe treatise which I had earlier intended to publish.* And Ihad then shown what structure the nerves and the muscles ofthe human body must have to enable the animal spirits, beinginside that body, to have the power to move its members, as weobserve in the case of severed heads, which we can see movingand biting the earth shortly after having been cut off, althoughthey are no longer animate. I had also shown what changesmust occur in the brain to cause states of waking, sleeping,and dreaming; how light, sounds, smells, tastes, heat, and allthe other qualities of external objects can imprint various ideason the brain through the intermediary of the senses; howhunger, thirst, and the other internal passions can also transmitideas to the brain; what must be taken to be the sensus com-munis* in which these are received, the memory which pre-serves them, and the faculty of imagination, which can changethem in different ways, form them into new ideas and, by the

same means, distribute animal spirits to the muscles and makethe members of this body move, with respect both to theobjects which present themselves to the senses and to theinternal passions, in as many different ways as the parts of ourbodies can move without being directed by our will. This willnot appear at all strange to those who know how wide a rangeof different automata or moving machines the skill of man can

make using only very few parts, in comparison to the greatnumber of bones, muscles, nerves, arteries, veins, and all theother parts which are in the body of every animal. For theywill consider this body as a machine which, having been madeby the hand of God, is incomparably better ordered and has initself more amazing movements than any that can be createdby men.

At this point I had dwelt on this issue to show that if therewere such machines having the organs and outward shape of amonkey or any other irrational animal, we would have nomeans of knowing that they were not of exactly the samenature as these animals, whereas, if any such machinesresembled us in body and imitated our actions insofar as thiswas practically possible, we should still have two very certainmeans of recognizing that they were not, for all that, realhuman beings.* The first is that they would never be able to usewords or other signs by composing them as we do to declareour thoughts to others. For we can well conceive of a machinemade in such a way that it emits words, and even utters themabout bodily actions which bring about some correspondingchange in its organs (if, for example, we touch it on a givenspot, it will ask what we want of it; or if we touch it somewhereelse, it will cry out that we are hurting it, and so on); but it isnot conceivable that it should put these words in differentorders to correspond to the meaning of things said in its pres-

ence, as even the most dull-witted of men can do. And thesecond means is that, although such machines might do manythings as well or even better than any of us, they would inevit-ably fail to do some others, by which we would discover that

they did not act consciously, but only because their organswere disposed in a certain way. For, whereas reason is a uni-versal instrument which can operate in all sorts of situations,their organs have to have a particular disposition for each par-ticular action, from which it follows that it is practicallyimpossible for there to be enough different organs in amachine to cause it to act in all of life’s occurrences in the sameway that our reason causes us to act.

Now we can also determine the difference between men andanimals by these two means. For it is a very remarkable factthat there are no men so dull-witted and stupid, not evenmadmen, that they are incapable of stringing together differ-ent words, and composing them into utterances, throughwhich they let their thoughts be known; and, conversely, thereis no other animal, no matter how perfect and well endowed bybirth it may be, that can do anything similar. Nor does thisarise from lack of organs, for we can see that magpies andparrots can utter words as we do, and yet cannot speak like us,that is, by showing that they are thinking what they are saying;whereas men born deaf and dumb, who are deprived as muchas, or more than, animals of the organs which in others serve

for speech, usually invent certain signs to make themselvesunderstood by those who are their habitual companions andhave the time to learn their language. This shows not only thatanimals have less reason than man, but that they have none atall.* For it is clear that we need very little reason in order to beable to speak; and given that as much inequality is foundamong animals of the same species as among men, and thatsome are easier to train than others, it is unbelievable that themost perfect monkey or parrot of their species should not beable to speak as well as the most stupid child, or at least a childwith a disturbed brain, unless their soul were of a wholly dif-ferent nature to ours. And speech must not be confused withthe natural movements that are signs of passion and can beimitated by machines as well by as animals; neither must oneimagine, as did certain ancient thinkers, that animals speak,

although we do not understand their language. For if that weretrue, they would be able to make themselves understood by usas well as by other members of their species, since they havemany organs that correspond to ours. It is also a very remark-able fact that although many animals show more skill in someof their actions than we correspondingly do, it is nonethelessclear than the same animals show none at all in many others, sothat what they can do better than us does not prove that theyhave any mental powers, for it would follow from this that theywould have more intelligence than any of us, and would sur-

pass us in everything. Rather, it shows that they have no men-tal powers whatsoever, and that it is nature which acts in them,according to the disposition of their organs; just as we see thata clock consisting only of ropes and springs can count thehours and measure time more accurately than we can in spiteof all our wisdom.

Following this, I had described the rational soul, and shownthat, unlike the other things of which I had spoken, it couldnot possibly be derived from the potentiality of matter, butthat it must have been created expressly. And I had shownhow it is not sufficient for it to be lodged in the human bodylike a pilot in his ship,* except perhaps to move its members,but that it needs to be more closely joined and united with thebody in order to have, in addition, feelings* and appetites likethe ones we have, and in this way compose a true man. I dwelta little at this point on the subject of the soul, because it is ofthe greatest importance. For, after the error of those who denythe existence of God, which I believe I have adequatelyrefuted above, there is none which causes weak minds to straymore readily from the narrow path of virtue than that ofimagining that the souls of animals are of the same nature asour own, and that, as a consequence, we have nothing more tofear or to hope for after this present life, any more than fliesand ants. But when we know how different flies and ants are,we can understand much better the arguments which provethat our soul is of a nature entirely independent of the body,

and that, as a consequence, it is not subject to death as thebody is. And given that we cannot see any other causes which

may destroy the soul, we are naturally led to conclude that itis immortal.*

PART SIX

It is now three years since I completed the treatise thatcontained all the above. I was beginning to revise it so that Icould place it in the hands of a printer, when I learned thatpersons to whom I defer, and whose authority holds hardly lesssway over my actions than my own reason over my thoughts,had condemned a physical theory, published a little earlier bysomeone else,* to which I would not want to go so far as to say Isubscribed, but only that I had seen nothing in it before theiract of censure which I could imagine being prejudicial toreligion or state, and which consequently would have pre-vented me from writing about it, if my reason had persuadedme to do so. This made me fear that there might be one of myown opinions in which I was equally mistaken, notwithstand-ing the great care I have always taken never to accept any newopinions for which I did not have very certain proof, and not towrite about any which might work to the disadvantage of any-one. This was enough to make me change the decision I hadtaken to publish my theories. For even if the reasons for takingthe decision earlier to publish were very strong, my naturalinclination, which has always made me dislike the business*of writing books, led me to find a host of other reasons forexcusing myself from doing so. And these reasons, both forand against, are such that not only do I have some interest

in declaring them here, but the public may also have someinterest in knowing what they are.

I have never laid great store by the products of my mind,and as long as I reaped no other benefits from the method thatI use (apart from satisfying myself about some problems thatbelong to the speculative sciences, or trying to direct my life bythe precepts that it inculcated in me), I have not felt obliged towrite anything about it. For as far as mode of life is concerned,everyone is so sure that they know best that one could find as

many reformers as there are people,* if it were permitted to anyother than those whom God has established as sovereigns overtheir peoples, or those to whom He has given sufficient graceand zeal to be prophets, to set about changing anything. Andalthough I was very pleased with my speculations, I believedthat others had their own which perhaps pleased them evenmore. But having no sooner acquired some general notionsabout physics, and begun to test them out on various particularproblems, I noticed where they may lead and how much theydiffer from the principles that have been employed up to now,and I believed that I could not keep them hidden withoutsinning greatly against the law that obliges us to procure, as faras it is in our power, the general good of all mankind. For thesenotions have made me see that it is possible to attain know-ledge which is very useful in life, and that unlike the specula-tive philosophy that is taught in the schools, it can be turned

into a practice by which, knowing the power and action of fire,water, air, stars, the heavens, and all the other bodies that arearound us as distinctly as we know the different trades of ourcraftsmen, we could put them to all the uses for which they aresuited and thus make ourselves as it were the masters andpossessors of nature.* This is not only desirable for the dis-covery of a host of inventions which will lead us effortlessly toenjoy the fruits of the earth and all the commodities that canbe found in it, but principally also for the preservation ofhealth, which is without doubt the highest good and the foun-dation of all the other goods of this life. For even the minddepends so much on the temperament* and disposition of theorgans of the body that, if it is possible to find some way ofmaking men in most cases wiser and more skilful than theyhave been hitherto, I believe that it is in medicine that it mustbe sought. It is true that medicine as presently practised con-tains little of such notable benefit; but without wishing to dis-parage it, I am certain that there is no one, even among thosewhose profession it is, who will not admit that what is knownabout it is almost nothing compared to what remains to be

known, and that it would be possible to be free of innumerableillnesses of both body and mind, and perhaps even the declineof old age, if we knew enough about their causes and theremedies with which nature has provided us.* So, intending to

devote my whole life to the pursuit of such an indispensablebranch of knowledge, and having found a path which, I think,will inevitably lead me to it, unless prevented from doing so bythe brevity of life or the lack of empirical information, I judgedthat there was no better remedy against these two obstaclesthan to communicate faithfully to the public what little I haddiscovered, and to urge good minds to try to go further bycontributing, each according to his inclinations and power, tothe observations and experiments* that need to be undertaken,and by communicating in turn to the public everything thatthey learn. Thus, as the last would start from where theirpredecessors had left off, thereby combining the lives andlabours of many, we might together make much greaterprogress than any one man could make on his own.

I noted, moreover, in respect of observations and experi-ments, that the further we progress in knowledge the morenecessary they become. For, at the beginning, rather than toseek out rarer and more contrived experiments, it is better toundertake only those which communicate themselves directlyto our senses, of which we cannot remain ignorant, providedthat we reflect a little on them. The reason for this is that rarerexperiments often mislead us, at a time when we do not stillknow the causes of more common ones, and the circumstanceson which they depend are nearly always so specific* and minutethat it is difficult to take good note of them. But the order towhich I have adhered in this regard is the following. First, Ihave tried to find in general the principles or first causes of

everything that exists or can exist the world, without consider-ing to this end anything other than God alone, who has createdit, and deriving these principles only from certain seeds oftruths which are naturally in our souls. After that, I came toexamine what are the first and most common effects which one

can deduce from these causes; and it seems to me that I have inthis way discovered the heavens, heavenly bodies, and an earth;and, on the earth, water, air, fire, minerals, and several othersuch things which are the most common and the simplest ofall, and hence the easiest to know. Then, when I wanted toproceed to more particular things, so many different ones pre-sented themselves to me that I did not believe it possible forthe human mind to distinguish the Forms or Species* of bodiesthat are on the earth from a host of others which might bethere, if it had been the will of God to put them there. Con-sequently, I did not think there was any other way to makethem useful to us, than by progressing from effects to causesand by engaging in many individual observations. Followingwhich, I cast my mind over all the objects that had ever pre-sented themselves to my senses, and I venture to declare that Ihave not noticed anything which I could not explain quiteeasily by the principles I had found. But I must also acknow-ledge that the power of nature is so ample and vast, and theseprinciples so simple and general, that I am able to observehardly any particular effect without knowing from the begin-ning that it can be deduced from the principles in many differ-

ent ways, and that my greatest difficulty is normally to find inwhich of these ways the effect depends on them. For I know ofno other means of achieving this than by seeking furtherexperiments and observations, whose results will vary accord-ing to the way the effect depends on my principles. For therest, I have now reached the point where I think I can see quiteclearly from which angle to approach most of the experimentsand observations which can serve this end. But I can see alsothat they are of such a kind and in so great a number, thatneither my industry nor my income (even if it were a thousandtimes greater than it is) could suffice for all of them. And so Iwill progress to a greater or lesser degree in knowledge ofnature, according to the means that I have from now on toundertake more or less of them. I undertook to myself to makethis known in the treatise I had written, and to show so clearly

the use the public may derive from it, that I would oblige allthose who desire the good of mankind in general (that is to say,all those who are truly virtuous and do not just pretend to be,or just have that reputation) both to communicate to me theexperiments and observations in which they have engaged andto help me in determining those which still need to be done.

Since that time I have, however, had other reasons to makeme change my mind and decide that I had indeed to go onrecording everything that I thought of some importance as Idiscovered the truth about it, and to bring the same care to thistask as if I intended to publish my results; as much in order to

have more opportunity to examine them (as, without doubt,we always take greater care over what we think will be seen bymany people than over what we do only for ourselves; andthings which have seemed true to me when I began to thinkthem out, have often seemed false when I have tried to setthem down on paper), as to lose no opportunity to benefit thepublic, if I can, so that, if my writings are of any value what-soever, those who will come into possession of them after mydeath will be able to make the most appropriate use of them.But I decided that I must never agree to them being publishedduring my lifetime, to avoid being given occasion to waste thetime I intend to use in acquiring knowledge, either on theopposition or the controversy to which they might be subject,or as a result of whatever reputation they might bring me. Foralthough every man is indeed bound to procure the good ofothers insofar as it is within his power, and we are, in the truemeaning of the word, worthless if we are of no use to anyoneelse, yet it is also true that our efforts have to reach out beyondthe present time, and that it is acceptable to omit doing thingswhich might bring some benefit to our contemporaries, whenthis is done in order to bring greater benefit to our grand-children. I would also like it to be known that the little I havelearnt up to now is almost nothing in comparison with what Ido not know, and what I have not yet given up the hope ofcoming to know; for those who gradually discover truth in the

sciences are more or less like people who, as they becomewealthy, have less difficulty in making great acquisitions thanthey had earlier in making much smaller ones, when poorer. Orthey can also be compared to military commanders, whoseforces usually grow in proportion to their victories, and whoneed more skill to maintain their position after defeat in battlethan they need to take towns and provinces after a victory. Forto try to overcome all the problems and errors that prevent usattaining knowledge of the truth is indeed to engage in battle.And when we embrace some false opinion on a quite generaland important matter, it is equivalent to losing one; muchmore skill is needed thereafter to regain the position we werein before, than in making great strides forward when we arealready in possession of principles which are certain. For mypart, if I have so far discovered a number of truths in thesciences (and I hope that the contents of this volume will causepeople to think that I have indeed found a few), I can say thatthey merely result from and depend on my having overcomefive or six principal difficulties, which I look on as so manybattles in which I had good fortune to be on the winning side. Ieven dare speculate that I need only to win two or three otherssimilar to these to fulfil my aims completely; and that I am notso advanced in age that I may not still have, in the ordinarycourse of nature, enough leisure to achieve this. But the

greater the hope I have of being able to spend the time thatremains to me usefully, the more I see myself obliged to man-age it carefully; and I would without doubt have manyopportunities of wasting it, if I were to publish the foundationsof my physics. For although they are nearly all so incontrovert-ible that one would only have to be apprised of them to believethem, and although there is not one among them which I donot think that I could prove, yet, since it is impossible thatevery one of them will be in agreement with all the differentopinions of others, I foresee that I would be often distractedfrom my work by the hostile reactions to which they wouldgive rise.

One might say that this opposition would be useful, as muchto make my errors known to me as to allow others, if I had gotsomething right, to understand it better; and since many cansee more than one man can see by himself, it would allow themto help me with their discoveries as they began to use my own.But although I acknowledge that I am extremely prone toerror, and that I almost never trust the first thoughts that cometo me, nevertheless, the experience I have of the objectionsthat can be made to my work prevents me from expecting anybenefit from them. I have already often encountered thejudgements, not only of those whom I have held to be myfriends and some I thought indifferent to me, but also of cer-tain others who, through malice and envy, would strive toexpose what my friends did not see because of their affectionfor me. But it has rarely happened that objections have beenmade which I had not at all foreseen, except those which were

not in any way pertinent to my work. Thus, I have almostnever come across a critic of my opinions who did not seemeither less exacting or less fair than myself. Nor have I everfound any previously unknown truth by means of the disputa-tions that are practised in the schools;* for as long as the parti-cipants are trying to win, they are more concerned to makeplausibility count than to weigh the two sides of the argument;and those who have long been good advocates do not necessar-ily go on to make better judges.

As for the benefit that others would receive from mythoughts being communicated to them, it might not be verygreat, seeing that I have not yet taken them so far that there isnot much that needs to be added to them before putting theminto practice. And I believe that I can say without vanity that ifthere is anyone capable of undertaking this, it must be myselfrather than someone else; not that there may not be incompar-ably better minds than mine in the world, but because wecannot so well grasp something and make it our own when welearn it from someone else as when we discover it ourselves.This is so true in this case that, although I have often explained

some of my opinions to people endowed with very fine minds,and who, as I was telling them about them, seemed to under-stand them very clearly, yet when they repeated them back tome, I noticed that they had nearly always changed them insuch a way that I could no longer acknowledge them as myown. I should like here to take this opportunity of asking

future generations never to believe that I am the source of theopinions people may tell them are mine, unless I have myselfpublished them. I am in no way surprised by the extraordinarythings which are attributed to all the ancient philosopherswhose writings have not come down to us, nor do I concludefrom this that their thoughts were very irrational (given thatthey were the best minds of their age), but only that they havebeen inaccurately reported to us. We see, too, that it has almostnever happened that any of their disciples have surpassedthem; and I am sure that the most passionate present-day fol-lowers of Aristotle would count themselves fortunate if theyhad as much knowledge of nature as he had, even on the condi-tion that they would never have more. They are like ivy, whichtends never to grow higher than the trees that support it, andoften even grows back down once it has reached their tops. Forit seems to me that modern Aristotelians also come back down,that is, make themselves in a certain way less knowledgeablethan if they had abstained from study. Not content with know-ing all that is intelligibly explained in their author, they wish,in addition, to find in his writings the solution to many prob-lems about which he says nothing and to which he perhapsnever gave any thought. However, their manner of phil-osophizing is very convenient to those who only have mediocreminds; for the obscurity of the distinctions and the principleswhich they use makes it possible for them to speak about thewhole range of knowledge as boldly as if they really knew it all,and to maintain everything that they say against the subtlest

and shrewdest thinkers, without there being a means of caus-ing them to change their minds. In this they seem to be likeblind men who, in order to fight on equal terms against those

who can see, lure them into the depths of some very darkcellar. I may say that it is in the interest of these people that Iabstain from publishing the principles of philosophy that I use;for as they are very simple and very certain, I would be doingthe same in publishing them as opening some windows, andletting the light of day into the cellar into which they havegone down to fight. But even the best minds have no reason towish to know my principles; for if they want to be able to speakabout everything and acquire the reputation of being learned,they will achieve this more easily by contenting themselveswith plausibility, which can without great difficulty be found inall kinds of matters, than in seeking the truth, which isrevealed only gradually in a few, and which requires, in anydiscussion of the others, that one frankly acknowledge one’signorance. If they prefer the knowledge of a few truths to thevanity of appearing to know everything (and the former is,without doubt, preferable), and if they wish to pursue a projectsimilar to mine, they do not in that case need me to say any-thing more to them than what I have already said in this dis-course. For if they are capable of going beyond what I havedone, they will be a fortiori capable of finding out for them-selves everything I think I have discovered. And as I havenever examined anything except in an orderly way, whatremains for me to discover is in itself certainly more difficult

and more hidden than what I have been able to discover up tonow, and they would have much less pleasure in learning itfrom me than for themselves.* Besides, the habit they willacquire of investigating easy things first and then progressingby degrees to other, more difficult matters will be of more useto them than all my instruction could be. And for my part, Iam convinced that if I had been taught from my earliest yearsall the truths which I have since sought to prove, and hadfound no difficulty in learning them, I might perhaps neverhave known any others; or at least I would never have acquiredthe habit and facility which I think I have of always findingnew ones, as I proceed to apply myself to search for them. In a

word, if there were in the world any one task which could notbe better accomplished by anyone other than the person whobegan it, it is the one on which I am working.

Admittedly, as regards the experiments and observationsthat may be of use to this task, one man alone could not pos-sibly do them all; but equally, he could not usefully employother hands than his own, except those of artisans or suchpersons as he could pay, in whom the hope of gain (a veryeffective spur) would make them do exactly what he told themto do. For as for volunteers, who might offer to help him out ofcuriosity or a desire to learn, apart from usually promisingmore than they end up giving, and having fine proposals, noneof which comes to fruition, they would inevitably wish to be

rewarded by having certain problems explained to them, or atleast by compliments and vapid conversations which could notcost him so little time that he would not lose out by theirinvolvement. And as for the experiments and observations thatothers have already made, even if they were willing to com-municate them to him (something which those who call themsecrets would never do*), they involve, for the most part, somany dependent circumstances and so many superfluousingredients that it would be very difficult for him to determinethe truth in them. Besides, he would find nearly all of them sobadly explained or even so false, because those who undertookthem had tried to make them appear to conform to their ownprinciples, that even if there were some of which he couldmake use, they could not be worth the time he would have tospend selecting them. So if there were someone in the worldwho was known for sure to be capable of making discoveries ofthe greatest importance and public benefit, and that for thisreason other men tried in every way possible to help him toachieve his ends, I do not see how they could do anything elsefor him, except to provide him with financial support for theexperiments and observations he would need to make, and, forthe rest, prevent his time being wasted by importunate visitsfrom other people. But while not being so presumptuous as to

be willing to promise remarkable results, nor entertainingthoughts so vain as to imagine that the public ought to take agreat interest in my projects, I do not also have so base a soul asto wish to accept from anyone whatsoever a favour which I

might be deemed not to have deserved.All these considerations taken together were the reason why,

three years ago,* I refused to publish the treatise that I had inmy hands, and why I had decided not to make public any otherwork in my lifetime which was so general, or from which onecould derive the foundations of my physics. But two otherreasons have since made me include here some individualessays,* and give the public some account of my actions andplans. The first is that if I failed to do so, many who knowabout my earlier intention to publish certain writings mightimagine that the reasons why I have abstained from so doingwere more to my discredit than they are. For although I am notexcessively fond of glory, and even, if I dare say so, hate it, inthat I judge it to be contrary to the tranquillity that I valueabove everything else, it is also the case that I have never triedto hide my actions as though they were crimes, nor have Itaken great precautions to remain unknown; not only because Iwould have thought that I would be doing myself an injustice,but also because doing this would have given me a certain sortof uneasiness which would also have been opposed to the per-fect peace of mind I am seeking. And because, although alwayshaving been indifferent to being well known or not known atall, I have been unable to avoid acquiring some sort of reputa-tion, I have come to think that I must do my best to avoidhaving a bad one. The other reason that has made me write is

that of seeing every day the project that I have, to acquireknowledge, suffering more and more delay; because of the vastnumber of experiments and observations I need to make, andwhich it is impossible for me to undertake without the help ofothers. Although I do not flatter myself with any expectationthat the public should share my interests, I do not, on the otherhand, want to fall so far below my own standards that I give

those who come after me cause to reproach me one day for nothaving left them many things in better order than I have done,if I had neglected to make them see how they could contributeto my projects.

I believed it to be easy for me to choose certain matterswhich, without having been the subject of many controversies,nor compelling me to declare openly more of my principlesthan I wished, would still reveal quite clearly what I am cap-able, or not capable, of in the sciences. I cannot tell whether Ihave succeeded in this, and I do not want to prejudice anyone’sjudgement by speaking myself about my writings. But I shallbe very glad for them to be critically examined, and so that onemight feel all the more free to do so, I beg all those who mayhave any objections to take the trouble of sending them to mypublisher, through whom, on being informed about them, Ishall try to deliver my reply at the same time. By this meansreaders, seeing together the objections and the replies, will beable more easily to judge where the truth lies. I do not under-take ever to make long replies, but only to admit my mistakesfrankly, if I perceive them, or, if I cannot see where they lie, to

say simply what I deem to be necessary in defence of what Ihave written, without proceeding to the explanation of anynew matter, so as not to get dragged along interminably fromone topic to the next.

If some of the things I speak about in the beginning ofthe Dioptrics and the Meteorology shock readers at first sight,because I call them ‘suppositions’ and do not seem to want toprove them,* I ask them to have the patience to read the wholeof the treatise attentively, and I hope that they will be satisfiedby it. For it seems to me that my arguments follow each otherin such a way that, if the last are proven by the first, which aretheir causes, the first are reciprocally proved by the last, whichare their effects.* And one must not imagine that I am commit-ting here the fallacy that logicians call a ‘circle’;* for as empiricalevidence* clearly confirms most of these effects, the causes fromwhich I deduce them do not so much serve to prove them as to

explain them; conversely, it is the causes that are proved by theeffects. And I have called them ‘suppositions’ only to make itknown that, while I think I can deduce them from the primarytruths that I have explained above, I have expressly decidednot to do this, in order to prevent certain thinkers from seizingthe opportunity of building some new outlandish philosophyon what they believe to be my principles, for which I should beblamed; thinkers who believe that as soon as one has said only

two or three words to them on a given matter, they can know inone day what it would take someone else twenty years to thinkout; and the more penetrating and lively these thinkers are, themore they are liable to err and the less capable they are of thetruth. As for the opinions that are wholly mine, I offer noapology for their being new;* for if the arguments supportingthem are carefully considered, I am certain that one will findthem so simple and so consistent with common sense, thatthey will seem less extraordinary and strange than any otheropinions which one might entertain on the same subjects. I donot boast of being the first discoverer of any of them, but Ido claim that I have accepted them, not because they have, orhave not, been expressed by others, but only because reasonpersuaded me of their truth.

And if craftsmen are unable straight away to construct theinvention explained in the Dioptrics, I do not believe that it canbe said on that account to be bad. In view of the fact that itneeds skill and practice to make and adjust the machines I havedescribed, without missing out any detail, I would be no lesssurprised if they succeeded at the first attempt, than if some-one could learn to play the lute expertly in a single day simplybecause he had been given a good fingering chart. And if Iwrite in French, which is the language of my country, ratherthan Latin, which is that of my teachers, it is because I hopethat those who use only their unalloyed natural reason will bebetter judges of my opinions than those who swear only bythe books of the ancients.* And as for those who combinegood sense with application, whom alone I wish to have as my

judges, I am sure they will not be so partial to Latin that theywill refuse to grasp my arguments because I express them inthe vulgar tongue.

For the rest, I do not wish to speak here in detail of thefuture progress I hope to make in the sciences, or commitmyself to any promises to the public which I am not sure ofbeing able to fulfil. I will simply say that I have decided todevote the rest of my life to nothing other than trying toacquire some knowledge of nature which may be such that wemay derive some rules in medicine which are more reliablethan those we have had up to now; and my inclination detersme so strongly from all other sorts of project, especially thosewhich can be only useful to some by harming others,* that ifsome situation arose which forced me to work on them, I donot believe that I would be capable of succeeding. On this Ihere am making a declaration that I know will not make meworthy of esteem in the world, but then I have no desire togain it. And I shall always consider myself more obliged tothose through whose favour I may freely enjoy my time with-out hindrance, than to those who might offer me the offices inthe world which are held in the highest esteem.

EXPLANATORY NOTES

too long to be read all at once: the Discourse is of course exceptionally short:Descartes is both commenting on the prolixity of his philosophicalcolleagues, and revealing his own dislike of reading long books: see AT ., ; . (letters to Mersenne, Oct. or Nov. , May , Sept. ); . – (a letter possibly to Huygens, ); . (Cogitationes privatae: ‘plerique libri, paucis lineis lectis figuris inspectis,toti innotescunt; reliqua chartae implendae adiecta sunt’), quoted abovein translation, Introduction, p. xxiv.

Good sense: the Latin translation has bona mens; this is a collocation usedby Seneca (Epistulae morales, . , . ; De vita beata, . ), but not inthis sense. In Descartes’s Regulae, , bona mens is glossed as ‘universalwisdom’ (universalis sapientia: AT . ); what is designated here is thefaculty of judgement which will allow us, if properly employed, to reachwisdom. Cf. letter to Mersenne, Oct. , AT . –: ‘all menhaving the same natural light [lumière naturelle, on which see below, noteto p. , ‘an inner light’], would seem to entail that all have the samenotions . . . but . . . hardly anyone makes good use of this light.’ Cf.Montaigne, Essais, ed. Pierre Villey (Paris ), . , : ‘it is usuallysaid that the most equitable distribution that nature has made to us of hergifts is that of the faculty of judgement’; also Romans : (see alsobelow, AT . , and note to p. , ‘as many reformers’): ‘let everyoneabound in his own sense.’ There are proverbs which make the samepoint: e.g. ‘there are as many opinions as there are men’ (quot homines totsententiae). The concept of ‘good sense’ is discussed in the interview withBurman, AT . . Its possession by all men does not, however, excludethere being different degrees of aptitude for abstract thought (see below,AT . ), or different degrees of success in using it correctly.For it is not enough . . . correctly: Descartes has to make this point, becausehe will later argue that the consensus of the wise (the acknowledgedexperts in a given field)––(what is known in Latin at this time asprobabilitas)––is not a sufficient argument to establish the truth of aproposition; the misapplication of good sense has led, in his contention,to the acceptance of many errors and the failure to discover many truths.the right road . . . stray off it: the image, of the road and travelling, whichrecurs in the Discourse, is probably borrowed from Seneca, De vita beata,. , a text which he recommends to the Princess Elizabeth (AT . ).This reminds us that Descartes had had an excellent humanist education,and that in spite of his declared hostility to reading, he had imbibedmuch of what he read.

make up an accomplished mind: the reference to reason (‘mind’), imagin-ation, and memory seems to be in accordance with traditional psych-ology, which assigned these faculties to three ventricles of the brain; butas will emerge later in the Discourse, reason, imagination, and memoryare all immaterial, and do not have given locations, but only a place forinteraction with the body (the pineal gland). See E. Ruth Harvey, TheInward Wits (London, ).

accidents . . . species: Descartes is here using scholastic vocabulary, anditalicizes the technical words he is borrowing; but he cannot be said toreproduce scholastic doctrine, according to which reason, which definesman as a species of animal, must be equally present in all men; it is thedegree to which the material part of man occludes its operation whichexplains difference of mental ability. Descartes cannot believe this, as hedoes not accept that there is any interaction between matter qua resextensa and mental activity qua res cogitans. There is a slight hint ofmockery in the way he introduces the terms, hinting that they are emptyverbiage. He makes use of this vocabulary at various points of theDiscourse; subsequent italicization is my own (unless otherwise stated).On his use of these terms, see also Introduction, pp. l–li, lxvi.

fashioned a method: method is defined in Regulae (AT . ) as havingfour characteristics: certainty in the distinction between truth and error,ease of application, fruitfulness, and wisdom or the production of trueknowledge.

vain and futile: i.e. philosophizing is the only non-futile human activity.The products to which Descartes refers include the treatises Le Monde(The Universe) and L’Homme (Man).

purely human occupations: Descartes consistently separates philosophyfrom theology or any grace-inspired speculations, and criticizes thosewho mix them together: e.g. Lord Herbert of Cherbury, whose Deveritate () is discussed in a letter to Mersenne of Aug. (AT . ). See also Introduction, pp. xii–xiii, on the possible hiddenreligious motive underlying his own practice of philosophy.

the reactions . . . to this picture: an allusion to the practice of the Greekpainter Apelles, who hid behind his canvases to hear what the publicwould say about them (hence the saying Apelles latens post tabulam); theLatin translation of the Discourse at this point makes the allusion explicitby citing the saying; Descartes refers to the practice in a letter toMersenne dated Oct. (AT . ).

tried to conduct mine: cf. Montaigne, Essais, ed. Pierre Villey (Paris, ). , pp. –: ‘others educate man; I am giving an account . . . of oneparticularly badly educated one . . . I’m not teaching, I’m telling a story’(‘les autres forment l’homme; je le recite . . . et en represente unparticulier bien mal formé . . . je n’enseigne poinct, je raconte’).

classical studies: lettres; Descartes was educated at the Jesuit Collège de laFlèche, where he received the standard humanistic education, whichextended beyond what we would understand by ‘letters’; in the next fewpages he sets out the curriculum he followed. See Introduction, pp. ix–x.

occult and recondite: a reference to the ‘low sciences’ of astrology, chiro-mancy, natural magic, and alchemy. Chiromancy had been condemnedand banned in a papal bull of .

oratory . . . delicacy and charm: oratory is the fruit of classical rhetoric;the poetry referred to comes from the pens of classical authors such asVirgil, Horace, Statius, Ovid, and Claudian.

books on morals . . . virtue: the two most cited ancient moralists wereSeneca and Plutarch; but these and other pagan writers will be attackedin the next paragraph for their un-Christian attitudes.

riches and honours: Descartes is here referring to a cynical adage about thefaculties of medicine and law: ‘Galen brings riches and Justinian honour;from other disciplines you gather chaff, from these two grain’ (‘datGalenus opes et sanctio Justiniana | ex aliis paleas, ex istis collige grana’).He seems to suggest that a complete education will include the higherfaculties of law and medicine, which are only taught in universities, notin Jesuit colleges; he went on to study the law himself at the Universityof Poitiers, but does not refer to this part of his education here. SeeIntroduction, pp. ix–x.

knights of old: ‘les paladins de nos romans’; Descartes is referring to themedieval tales of heroic chivalry which were still popular in his day.

thickest of dialects: bas breton: the dialect of lower Brittany was particu-larly decried in Descartes’s day for its barbarity; in his unpublishedPursuit of Truth (Recherche de la vérité), Descartes cites Swiss Frenchwith Breton as particularly rustic dialects. Montaigne makes the samepoint about the natural powers of argumentation found among theuninstructed (Essais, ., p. ).

incontrovertibility: evidence: on this term, see the Introduction, p. l.

mechanical arts: at La Flèche geography, hydrography, military arts, andmechanics were taught, in addition to the subjects prescribed in theJesuit Ratio studiorum, on which see Introduction, pp. ix–x, and StephenGaukroger, Descartes: An Intellectual Biography (Oxford, ), –.

lack of human feeling . . . parricide: see above, note to p. ‘books onmorals . . .’. This is the traditional Christian line of attack on Stoicphilosophy; Descartes, like many of his contemporaries, approves ofother versions of Stoic philosophy, such as the Handbook of Epictetus:see Introduction, p. lii.

. . . more than merely human: Descartes is referring to divine grace; inCatholic theology, this confers on those who receive it (for example,

ordained priests) powers in excess of merely human mental capacities,and qualifies them to discuss doctrine and interpret Holy Writ. On hisreticence about his own divine calling, and his keenness to avoid anysuggestion that he was laying claim to special powers, see note to p. ,‘purely human occupations’ above, and Introduction, pp. xii–xiii.plausible: vraisemblable. Descartes consistently tries to rid himself of themiddle category of merely plausible propositions, those described by theLatin terms probabiles (i.e. being approved of by the wisest in a givenarea, or being derived from textual authority) and verisimiles (i.e. thatwhich can plausibly be derived from the evidence of the senses). Thesewere accepted in such disciplines as law and medicine: see Ian Maclean,Logic, Signs and Nature in the Renaissance: The Case of Learned Medicine(Cambridge, ), –; see also below, note to p. , ‘the majorityview’.the habit of Cynics: a reference to the ancient philosophical sect whosemost famous member was Diogenes of Sinope (c.–c. ).the low sciences: there is a subsequent reference to these hermetic andoccult arts and their habit of preserving ‘secrets’: see below, p. .Descartes is very keen to have his own practice of science, and his ownpromises of providing enlightenment, clearly distinguished from them.

had persuaded me of: Descartes attributes here to his experience whathe also might have learned from his reading of Montaigne’s Essais(especially . , . , and . ).

emotional turmoil: passions: Descartes was to write a treatise entitled ThePassions of the Soul in the s, in which the term reflects neo-Stoic usage, and designates those perturbations of the mind which areoccasioned by consideration of future, present, or past good or evil.a small room . . . at leisure: the Thirty Years War, to which Descartes isreferring here, lasted from to ; the coronation in question wasthat of the Holy Roman Emperor Ferdinand II at Frankfurt am Main,which took place between July and September . The armymentioned here is that of the Catholic Elector Maximilian, duke ofBavaria. The quarters are thought to have been either in a village nearUlmor or near Neuburg. The single day of solitary reflection andenlightenment in the stove-heated room referred to here is dated byDescartes’s early biographer Adrien Baillet to November .designs . . . on an empty plain: Descartes may have in mind the town ofRichelieu, designed de novo by the architect Lemercier to a strict geo-metrical pattern on a plain, and built in the s for the chief ministerof France, Cardinal Armand du Plessis de Richelieu; this was situatedless than km from his family’s possessions in Poitou.

contrary to good morals: Descartes is here apparently breaking his ownrule about passing value judgements on the customs and morals of other

nations (see above, AT . ). Among the practices he may have in mindare the exposure on hillsides of deformed children, the encouragementgiven to citizens to spy on one another, nudity in gymnastics for bothsexes, and women shared as sexual partners by certain groups.

by one man: the single lawgiver of Sparta was reputed to be Lycurgus.

. . . guided by that alone: Descartes offers a model of human developmentin which the immaterial soul gradually frees itself from the material body,in which are located ‘[animal] appetites’. This has implications both forthe relationship between will (the ‘rational appetite’) and desire, and thenature of the will itself, which are not fully worked out until the treatiseon the Passions of the Soul. See below, note to p. , ‘an inner light’.

in schools for teaching it: reference to the Aristotelian curriculum in theschools, on which see Introduction, pp. ix–x; Descartes does not wish todeclare himself to be a revolutionary, but clearly intends to be one.

political judgement: prudence (prudentia, phronesis): the faculty traditionallyassociated with ‘practical’ philosophies (politics, ethics, and domesticmanagement). The sentiments expressed here, and those which follow,are very close to those to be found in Montaigne, Essais, . and . .

more lofty designs: on the privileges bestowed by divine grace, see notes topp. , ‘purely human occupations’ and , ‘lack of human feeling’, above.

less capable . . . themselves: this seems to be in conflict with the notion of agenerally equal distribution of good sense expressed at the beginning ofthe Discourse.

no opinion . . . some philosopher or other: reminiscence of Cicero, De divina-tione, . . : ‘in some way or other there is nothing so absurd that canbe said that has not been said by one or other of the philosophers’ (‘sednescio quo modo nihil tam absurde dici potest quod non dicatur ab aliquophilosophorum’).

the majority view: la pluralité des voix (Latin: multitudo suffragiorum). Itseems likely that Descartes has in mind here either the definition of‘probable’ given in Aristotle’s Topics (i. , b f., as ‘generallyaccepted . . . commending itself to all or to the majority of the wise’, orits legal equivalent, known as ‘common opinion’ (opinio communis), onwhich see Ian Maclean, Interpretation and Meaning in the Renaissance:The Case of Law (Cambridge, ), . We may note again Descartes’saversion to accepting plausibility in any of its guises.

the art of Lull . . . anything new: the Catalan philosopher and theologianRaymond Llull (–?) set out to provide in his Ars magna auniversal method of discovery. Isaac Beeckman discussed Llull withDescartes (AT . , –), but it appears that Descartes nevertook the text seriously (AT . ). It was commonly argued againstsyllogisms that they revealed nothing new.

block of marble: Descartes here wittily adapts an analogy from Aristotelianphilosophy for his own purposes; in Physics, i. (b ), Metaphysics, iii. (a –), and v. (b –), Aristotle uses the example of a statueof ‘Hermes’ (not Diana or Minerva) being in the stone from which itwill be carved to show the distinction between potentiality and actuality;Descartes has no time for this metaphysical distinction.slave to certain rules and symbols . . . cultivates it: on Descartes’s revisionof the mathematical notation of his day, see Introduction, pp. lxii–lxiii.He is likely to have encountered modern versions of mathematics both inLa Flèche, where the work of the Jesuit defender of mathematics Chris-tophorus Clavius was known, and in Paris in the Mersenne circle, mem-bers of which were aware of the work of recent French scholars such asFrançois Viète.The first . . . no occasion to doubt it: on these precepts, see Introduction,pp. xlix–li.positing: supposant: this usage is close to that of natural philosophers ofDescartes’s generation, for whom suppositiones are ‘those things whichmust be accepted from the outset before a science can be constructed––definitions, statements of existence and undemonstrated (though notunjustified) principles generally’ (Peter Dear, ‘Jesuit Mathematical Sci-ence and the Reconstitution of Experience in the Early SeventeenthCentury’, Studies in the History and Philosophy of Science, (), ).Reasoning ex suppositione assumes that the empirical fact, the process, tobe explained––acorns developing into oak-trees, for example––was takenor supposed to have actually occurred without impediment (WilliamWallace, Prelude to Galileo: Essays on Medieval and Sixteenth-CenturySources of Galileo’s Thought (Dordrecht, ), –). The question ofsupposition will come up again (see AT . , –, ); here Descartesmerely attributes supposition to the order in which a problem isaddressed.a natural order of precedence: the order suggested here by Descartes doesnot specify which the ‘most easily understood objects’ are; in traditionalAristotelian terms, a distinction is made between that which is ‘betterknown by its nature’ and that which is ‘better known to us’ (Prior Analyt-ics, b –; ii. , b ff. Physics, i. . a –; Metaphysics, i. ,a ). The latter is known initially through the senses; the former is auniversal which is derived from the accumulation of sensory particulars(Prior Analytics, ii. ). The nature of knowledge received into the mindis such that universals are better known to it than the particulars ofsensory experience. The alternative ancient view is the Platonic view ofreminiscence (on which see Meno, A ff.), according to which there isno such thing as discovery, because if we do not know, we will not recog-nize what we have found, and if we know in fact, then we have no reasonto enquire. What is in question here is both the method of discovery of

universal terms in ‘science’ and the method of presentation of the resultsof such enquiry; Descartes presents his method as one of discovery, anddoes not concern himself here with the pedagogical implications of theorder of presentation. His argument that metaphysics precedes physicsrelegates sensory knowledge from its primordial place: see Introduction,p. li.

. . . left nothing out: the three elements of the method––division, simplifi-cation, enumeration––are interdependent and imply each other (Regulae,, AT . ); they also can have a relationship to induction (ibid., AT. ), but only in cases where the cases cited show that no other casecan be later conceived which would invalidate the conclusion (e.g. thatthe area of a circle is greater than all other figures having the sameperiphery). Each element of the enumeration for Descartes is confirmedby the intuition of its clearness, distinctness, and evidentness as a reliablebuilding-block for further deductions; such a test is much more rigorousthan the empirical version of induction set out, for example, by FrancisBacon in Book of his Novum organum.

. . . one cannot discover it: this is Descartes’s version of the mos geometri-cus, which is praised as a procedure by a number of ancient philosophers(among them Galen), and their Renaissance followers (Cardano).under the name of mathematics: in Descartes’s day, it was habitual todistinguish pure mathematics from mixed mathematics, which includedastronomy, astrology, music, mechanics, and optics.these proportions in general: a simple set of proportions are equality, beinggreater, and being less (a = b; a > b; a < b); Regulae, (AT . )divides these relations into two categories, order and measure. Orderrequires nothing other than sequence (a, b); measure requires a thirdterm (a unit which is the common measure).to my imagination: whether proportions should be thought about withvisual aids or only with the use of symbols is discussed in Regulae, –,AT . –. Below (AT . –) Descartes states that imagination hasno role to play in metaphysical speculation; he makes the contrast withmathematics very clear in a letter to Mersenne of November (AT . ): ‘the part of the mind which is of most use in mathe-matics, namely the imagination, is more of a hindrance than a help inmetaphysical speculations’; see also AT . .

briefest possible symbols: on the elegance of Cartesian notation (which wassubstantially achieved also a little earlier by Thomas Harriot, althoughthere is no way of showing that Descartes was aware of this), see above,note to p. , ‘slave to certain rules . . .’ and Introduction, pp. lxii–lxiii.months I spent investigating them: according to Étienne Gilson, Discoursde la méthode: texte et commentaire (Paris, ), –, the period inquestion must lie between December and February .

other branches of knowledge: Descartes has in mind especially physics ornatural philosophy (he describes himself as ‘physico-mathematicus’ evenbefore : see AT . ).

a provisional moral code: it has been argued that Descartes claimed to haveachieved considerable progress towards a definitive version of ethics, andthat this is enshrined in the Treatise on the Passions, which appeared in: see Anthony Levi, French Moralists: The Theory of the Passions to (Oxford, ), –; but in the preface to the Principia(AT . ) the ‘highest ethics’ is said only to be possible after a completegrasp of all other branches of knowledge had been achieved.

customs of my country: on obedience to local custom, see note to p. ,‘political judgement’.

. . . rather than what they said: Montaigne makes the same point aphor-istically (Essais, . , ): ‘the true mirror of our discourse is the courseof our lives’ (‘le vray miroir de nos discours est le cours de nos vies’).

. . . know that we believe it: this distinction is made in more general termsby Aristotle (in knowing the object of our mind’s thought, we know at thesame time our mind: De anima, iii. –); this gives rise to much specula-tion about the relationship of the mind to the knowledge of itself as anobject of thought in the Renaissance (see Ian Maclean, ‘Language in theMind: Reflexive Thinking in the Late Renaissance’, in Philosophy in theSixteenth and Seventeenth Centuries: Conversations With Aristotle, ed.Constance Blackwell and Sachiko Kusukawa (Aldershot, ), –). Descartes seems here to be dividing an act of the will (thejudgement that something is good or bad) from the intellect’s awarenessof that judgement. Both the will and the intellect fall within the cogitatioor thinking which provides the immediate intuition of existence: seePrincipia, . , AT A. .

most certain ones: constamment: a word which evokes neo-Stoic virtue, onwhich see Introduction, pp. lii–liii.

probability: probabilité: on this term, see above, notes to pp. , ‘For it isnot . . .’; , ‘more than merely human’; and , ‘the majority view’.

. . . as far as we are concerned: on the parallel of this sentiment, and thosewhich follow, with the philosophy of Epictetus, see Introduction, p. lii.

periods of meditation: Justus Lipsius’ Introduction to Stoic Philosophy(Manuductio ad stoicam philosophiam, . ) of ends with an exhort-ation to long meditation; Descartes would also have been familiar with StIgnatius Loyola’s Spiritual Exercises, which also prescribe this form ofmental activity. The Meditations of may well owe their title anddivision into six parts to the latter author’s work.

rival their gods in happiness: a reference to ancient Stoic philosophers, andmore especially to a text in Seneca (Epistulae, . : ‘a god has no

advantage over a wise man in respect of happiness, even though hehas such an advantage in respect of years’ (‘deus non vincit sapientemfelicitate, etiam si vincit aetate’).

however favoured . . . they may be: a reference to Cicero’s Paradoxastoicorum, (‘that the wise man [i.e. the Stoic sage] alone is free’) and (‘that the wise man alone is rich’).

an inner light: this is the natural light of reason discussed in Cicero’sTusculan Disputations, . . It was a phrase taken up by occult philo-sophers such as Oswald Croll at the beginning of the seventeenthcentury, and contrasted with the light of grace: ‘two lights are knownfrom which comes all perfect knowledge and besides which there is none.The light of grace gives birth to the true theologian, when accompaniedby philosophy. The light of nature brings the philosopher into being,when accompanied by theology, which is the foundation of true wisdom.’Their critics point to the risks of disciplinary anarchy in such a doctrine:‘they make up some light of nature and grace or other,’ writes DanielSennert, ‘with which they disguise the figments of their brain that cannotbe proved by either reason or experience. If it is permitted for any newdogma to be brought forth free of all experience and reason, and thatcredence should be given to it by simple reference to the light of natureand of grace, the result will be that truth will be what it seems to be toanyone. No-one can fail to see what confusion would come from this inevery discipline.’ See Maclean, Logic, Signs and Nature, –. Des-cartes is not writing in the context of this debate, but is aware of theproblem which arises when the ‘light of nature’ is invoked; his solution(sometimes called the ‘rationalist’ one) is to argue that the mind possesses(innate) fundamental truths independent of the senses from which it ispossible to deduce the elementary truths of mathematics and naturalphilosophy.

. . . to do our best: this is very close to the Thomist doctrine expressed inSumma Theologiae, a ae , , according to which the will is a rationalappetite which desires what is good, or what it perceives to be good(hence correct judgement equates to virtue, and vice to error; or asDescartes puts it in a letter to Mersenne dated April , ‘anyonesinning sins out of ignorance’. The rational appetite is distinguishedfrom the animal appetite (already invoked: see above, note to p. ,‘guided by that alone’).

the next nine years: i.e. from to ; for an account of the knowntravels of these years, see Gilson, Discours, –, Stephen Gaukroger,Descartes: An Intellectual Biography (Oxford, ), –, and Gene-viève Rodis-Lewis, Descartes: His Life and Thought, trans. Jane MarieTodd (Ithaca and London, ), –.

reach a decision: Descartes is here referring to a specific Pyrrhonist

(sceptical) practice of countering any proposition with its opposite, andsuspending judgement (the ways of arguing known as phonoi skeptikoi). Itis described by Montaigne, in Essais, . , pp. –. How seriouslyDescartes took this doctrine to be a threat to good philosophical practiceis a matter of dispute. He employs doubt as a means of establishing whereerror lies, not as an excuse for suspension of judgement.

many experiences: expériences (Latin: experimenta): this word can denotethe products of sensory perception, or experiments; it will be translatedas ‘observations and experiments’ when it occurs in contexts in which itssense is not restricted to one or the other of these meanings. See PeterDear, Discipline and Experience: The Mathematical Way in the ScientificRevolution (Chicago and London, ).

. . . dealt with in this volume: Descartes may be referring here particu-larly to the laws of sines which are discussed in the Dioptrics and thediscussion of the rainbow in the Meteorology.

than read books: on Descartes’s aversion to reading see above, note to p. ,‘too long’.

excellent minds . . . succeeded: see Introduction, pp. xlix–l, for more mod-ern names: Descartes may be referring here also to Aristotle (especiallythe Posterior Analytics) and Galen (the Ars parva).

to retire here: Descartes moved to Holland in ; the war to which he isreferring is that between the United Provinces and Spain, which lastedfrom to , with a truce from to .

. . . the most populous cities: cf. Introduction, p. xi (letter to Balzac of May , AT . ).

our senses sometimes deceive us . . . imagine it to be: doubting the evidence ofthe senses is of course a commonplace, much employed to reduce man’spresumptuous confidence in the knowledge he possesses. Descartes linksit here to the question of the illusory experiences of dreams.

. . . accepted as valid proof: Descartes omits here the argument of the‘malin génie’, which appears in the first Meditation (AT . –); therehe conjures up a powerful and ingenious demon who devotes all hisefforts to making him believe what was not true. It is possible that hethought that this was too radical and threatening for his non-professionalreaders.

I am thinking therefore I exist: the Latin version reads cogito ergo sum,which is normally translated as ‘I think therefore I am’; but the glossesthat Descartes places on this elsewhere (notably in the second parts of thePrincipia and the Meditations) make it clear both that it is a performative(‘I am thinking’) and that being is existing; he is not referring to being asessence: cf. Principia, . , AT B. : ‘it is contradictory to suppose thatwhat is thinking does not, at the very time when it is thinking, exist.’ Two

other points emerge from this passage: the first step towards the cogito isin fact the dubio (‘I am doubting, therefore I am existing’); and theimmediacy of this intuition is not consistent with the view expressed byother Renaissance figures who consider reflexive thinking, such asCardano, who see a time interval elapsing between the thought and therealization that the thought is being thought (De libris propriis, ed. IanMaclean (Milan, ), ): ‘we do not know and know that we areknowing in the same moment, but a little before or after’ (‘eodemmomento non intellig[i]mus, et cognosc[i]mus nos intelligere, sed pauloante vel post’). For a different critique of the human subject being simul-taneously the object and subject of its own enquiry, see Anthony Kenny,The Anatomy of the Soul: Historical Essays in the Philosophy of Mind(Oxford, ).

certain: assurée; from now on, évidence is equated with certainty. Thereply to the sceptics takes their rallying-cry epecho (‘I doubt’) and showsthat it entails existence. Both Mersenne (as revealed by Descartes’s letterto him of May : AT . ), and Antoine Arnauld in his objec-tions to the Meditations (AT . ), point to the fact that a similarargument appears at various points in St Augustine’s writings: De liberoarbitrio, . . ; De civitate Dei, . ; also De trinitate, . . . Herethe reply to the sceptical attack on the knowledge of the self, ‘what if youare wrong?’, reads ‘if I am wrong, I am’ (si fallor, sum). Descartes firstclaimed not to have used the argument in the same way as Augustine, andreturned to the point in a later letter of December (AT . ),where he links it with the supposed similarity Mersenne must have per-ceived between Descartes’s (a posteriori) proof of God’s existence andthe (a priori) ontological proof of God by St Anselm, on which see noteto p. , ‘which was God’, and Introduction, p. lvii.principle . . . I was seeking: this first principle is not the same as a syllo-gistic premiss or conclusion, but some of Descartes’s contemporariestried to translate it into those terms, to his manifest annoyance: seeIntroduction, p. lv.

the Soul: Ame: the capitalization makes clear that Descartes wishes theword to be read in its highest (theological) context; a usage reinforced bythe previous use of ‘substance’ and ‘essence’. Ce moi (‘This I’), whichturns the first-person pronoun into a noun, is a neologism; but it wouldbe mistaken to believe that, without it, a certain sort of objectified ortranscendental self-reference was not possible. Cf. Montaigne’s use ofâme with the first-person pronoun in Essais, . , p. .

. . . lacking something: it is a Cartesian principle that truth consists inbeing, and falsity only in non-being: see the letter to Clerselier of April (AT . ): ‘it is clear to me by the natural light [see above,note to p. , “an inner light”] that all deception depends on a defect; fora being in which there is no imperfection cannot tend to non-being, that

is, cannot have non-being, or non-goodness or non-truth as its end andpurpose, for these three are the same’ (‘omnem fraudem a defectupendere, mihi est lumine naturali manifestum; quia ens in quo nulla estimperfectio, non potest tendere in non ens, hoc est, pro fine et institutosuo habere non ens, sive non bonum, sive non verum; haec enim triaidem sunt’).

. . . that something should proceed from nothing: Descartes refers here to apremiss of both atomistic and Aristotelian physics (‘nihil ex nihilo fieri’),which was condemned by the bishop of Paris in because it wasinconsistent with the Judaeo-Christian doctrine of creation; he employsit here, as in his reply to the third objections to the Meditations (AT . )makes explicit, to argue that ‘there is no thing, nor any actual existingperfection of a thing, which can have nothing or a non-existence thing asthe cause of its existence’ (‘nulla res, nec ulla rei perfectio actu existens,potest habere nihil, sive rem non existentem, pro causa suae existentiae’).

. . . which was God: Descartes’s proof of God is compared by his con-temporaries to the (a priori) ontological proof of God’s existence by StAnselm, to which Mersenne drew Descartes’s attention (see AT . ),in which God is defined as a being than which nothing greater can beconceived, and it is argued that such a being cannot exist in the under-standing alone, but must exist in reality, which is greater than that whichresides only in the understanding. It is also compared to the proof of Godoffered by Aquinas in Summa Theologiae, a , by Pierre Bourdin in thefirst objections to the Meditations (AT . –). There is a very clearaccount of these complex and disputed arguments, and their relation-ship to Descartes’s own argument and its claim to be novel, in Gilson,Discours, –.

to have, of myself . . . participation . . . knew myself to lack: the italicizedwords are those which Descartes is using in a technical way (‘I shall herefreely employ, with your permission, some scholastic terminology’). Infact, he had begun earlier with substance and essence.

manifestly a defect: because the parts of a composite thing depend on thewhole, and the whole on the parts, both are seen as lacking the perfectionof independent existence.

or other intelligences: intelligences: immortal incorporeal beings inscholastic philosophy.

. . . without Him: the doctrine that God intervenes at every moment in hiscreation to ensure its continuing existence is known as occasionalism; theunique feature of Cartesian occasionalism is that it is not linked to sub-stantial forms or essences; see Gilson, Discours, –. This, and suchattributes as infinite and eternal, were much discussed in Descartes’stime in natural philosophy and medicine: see Maclean, Logic Signs andNature, –.

proof that God . . . exists: this argument, known as the ‘ontological proof’,was widely attacked by Descartes’s contemporaries (see AT . , ,, , , , – and above, note to p. , ‘which was God’).

unimaginable . . . unintelligible: on the use of imagination, see above, noteto p. , ‘to my imagination’.

. . . previously been in the senses: on the Aristotelian adage ‘Nil in intellectuquod non fuerit prius in sensu’, see Introduction, p. li. Descarteseffectively reverses the adage.

we possess an assurance: une assurance morale: by ‘moral assurance’ is meanthere a certainty sufficient for ordinary practical purposes: Principes, ,AT . –.

. . . comes from Him: this passage gave rise to the objection that the argu-ment was circular: it was alleged that Descartes determines an idea to beclear and distinct because God exists, is the author of the idea, and isnot a deceiving God; and determines that there is a God, that He isthe creator, and that He is the source of all truth and nothing buttruth, because there is a clear and distinct idea of Him: see Gassendi’scomments in the fourth objections to the Meditations, AT . .

. . . not wholly perfect: an expanded version of this condensed passage ofreasoning is found in Meditations, , AT . ff.

. . . without our being asleep: on the relation of this passage, in whichdreams are taken to be material, and Descartes’s prophetic dream of November , see Introduction, pp. xii–xiii.

a chimera exists in the world: reminiscence of Aristotle, De interpretatione,i. , a f.: ‘tragelaphos [goat-deer], while it means something, has notruth or falsity in it, unless in addition you predicate being or non-beingof it.’

must infallibly: Descartes felt uncomfortable about the strength of thisclaim, and approved of the change of ‘infallibly’ to ‘rather’ (potius) in theLatin translation of .

certain considerations . . . from publishing: on Galileo’s trial, and Des-cartes’s correspondence with Mersenne, see Introduction, pp. xxviii–xl.Two parts of the treatise mentioned here (Le Monde; L’Homme) werepublished posthumously from (incomplete) manuscripts: see AT .–.

if God . . . in imaginary space: this hypothesis at one remove allows Des-cartes to avoid citing condemned doctrines after the condemnation ofGalileo: see Introduction, p. xxxviii. In considering this hypotheticaluniverse, he avoids also taking a position over the finiteness or infinite-ness of the universe, insisting only that it is for his purposes indefinite(Principia, . , AT A. –), and citing later, in a letter to Chanut of June (AT . ), one Church authority (the fifteenth-century

bishop Nicholas of Cusa) on his side: ‘I remember that Cardinal Nicholasof Cusa and many other doctors [of the Church] have supposed theuniverse to be infinite, without ever being reprimanded by the Church onthis point.’

forms or qualities: on the setting aside of these terms, see Introduction,pp. l–li.

on the subject of light: on the content of the treatise on light, see Introduc-tion, p. xxvii.

conferred no weight: pesanteur: in scholastic terms, the tendency of bodiesto go downwards (see Aristotle, On the Heavens, ).

. . . by which He created it: on this doctrine, see Aquinas, SummaTheologiae, a . ad .

casting doubt upon the miracle of creation: on the sensitivity of this point,see above, note to p. , ‘that something should proceed from nothing’,and Introduction, p. xxviii.

rational . . . vegetative or sensitive soul: on the Aristotelian theory of thetripartite soul see Harvey, The Inward Wits. All that is left after thissubtraction is extension and movement.

. . . same time as the heart: this perpetuates the Galenic view, according towhich the pulse corresponds to diastole and is the active phase, andsystole is the passive phase of muscular relaxation in the heart; Harvey’sview that systole is the active phase is now taken to be correct againstDescartes.

. . . counterweights and wheels: the point of this passage––the reduction ofthe movement of the heart to a mechanical explanation (i.e. the subtrac-tion of any reference to occult forces)––is forcefuly made by this analogy.

English doctor . . . on this subject: the marginalium here reads ‘Hervaeus, demotu cordis’; the reference is of course to William Harvey’s On the Motionof the Heart and Blood in Animals (), a text to which Mersenne drewDescartes’s attention (see the letter to Mersenne of November orDecember , AT . ). What follows is a detailed refutation ofHarvey’s account of the operation of the heart. Descartes is careful topoint out that he had reached his own view about circulation beforehaving read Harvey, just as he had made the advances in mathematicswithout having read François Viète (AT . ); his own experiments onanimals to establish the mode of the heart’s operation are recounted ina letter to Vopiscus Plempius (–) dated February (AT. –).

various humours: humeurs: this word is usually reserved for the fourhumours which go to make up the temperament or complexion (blood,choler, yellow bile, and black bile, corresponding to sanguine, choleric,phlegmatic, and melancholic); but Descartes uses it here and in the

Treatise on Man (AT . –) to designate the transformations of bloodinto saliva, urine, sweat, and other excreta.

animal spirits: the name of one of the three Galenic spirits: natural, whichconstitutes the powers of appetite, change, and generation; vital, whichanimates the heart; animal, the source of rational thought and its lesserequivalent, the vis aestimativa, in animals; in Descartes’s mechanisticaccount, animal spirits are simply the smallest particles of the blood, andhave no vital functions.

subtle: subtil: composed of very small, fast-moving particles.

intended to publish: viz. Le Monde; L’Homme, on which see Introduction,pp. xxiii–xxviii.

to be the sensus communis: see Introduction, p. lvi.

. . . real human beings: the theory that animals are no more than machinesled to some disagreeable results: Descartes’s disciple, the theologianNicolas Malebranche, is said to have kicked a pregnant dog, and then tohave chastized such critics as Jean de La Fontaine, the French writer ofanimal fables, for expending their emotions over an unfeeling machinethat moves and makes noises depending merely on how and where it isstimulated, rather than concerning themselves with human misery.

. . . they have none at all: Descartes may well have in mind the long(polemical) defence of the reasoning powers of animals in Montaigne’s‘Apologie de Raymond Sebond’ (Essais, . ).

like a pilot in his ship: the analogy is taken from Aristotle, De anima, . ,a –.

feelings: sentiments: this term can denote both sensations and beliefs.

to conclude that it is immortal: on the currency of the debate about theimmortality of the soul, see Introduction, pp. lvii–lviii. Gilson, Discours,–, points out that Descartes is only able to claim that the soul ispossibly immortal, since its continuing existence would depend entirelyon God.

published . . . by someone else: a reference to Galileo, Dialogue Concerningthe Two Chief World Systems (), condemned by the Congregation ofthe Holy Office, in ; see Introduction, pp. xxxiii–xxxiv.

the business: métier: Descartes’s sense of his aristocratic status is apparenthere: see Introduction, p. viii.

as many reformers as there are people: this is the negative version of thestatement which opens the Discourse: see above, note to p. , ‘Goodsense’.

the speculative philosophy . . . possessors of nature: the speculative phil-osophy of the schools is of course Aristotelianism; Descartes’s hope thatmen might become the ‘masters and possessors of nature’ is consonant

with the programme set out by Francis Bacon in the Instauratio magnaand the Novum organum (. )on the temperament: tempérament: the combination of the four humourswhich is idiosyncratic to each individual.

be free of innumerable illnesses . . . old age . . . provided us: the prolongationof life was one of the ambitions of alchemy.experiments: expériences: on this term, see above, note to p. , ‘manyexperiences’.specific: particulières: peculiar to a set of circumstances.

Forms or Species: Descartes capitalizes these two words to mark his use ofthem in their scholastic meaning.

the disputations . . . in the schools: on Descartes’s strong reservations aboutdisputations, see the preface to the French edition of the Principes, ATB. –.

learning it . . . for themselves: having talked about divulging his physics,Descartes now hides it: his motive appears to be to prevent others fromclaiming that they are continuing his work. The gesture is similar to hispractice of setting very difficult or incomplete geometrical problems forhis correspondents, on which see Introduction, pp. xx, lxii–lxiii.

. . . would never do: a reference to the practice of alchemists: see Introduc-tion, p. xiii.

three years ago: i.e. in . Descartes is probably referring to his ‘open’letter of April , on which see Introduction, p. xxxvi.some individual essays: Dioptrics; Meteorology; Geometry, on which seeIntroduction, pp. lx–lxiii.

. . . ‘suppositions’ . . . to prove them: it is not clear how this relates to theclaim to have worked out everything from first principles.if the last are proven by the first . . . their effects: there is a reference hereto the logical procedure known as regressus (the passage from a demon-stration from effect to one from causes), on which see Nicholas Jardine,‘The Epistemology of the Sciences’, in The Cambridge History ofRenaissance Philosophy, ed. Charles B. Schmitt, Quentin Skinner, andEckhard Kessler (Cambridge, ), –, and Introduction, pp.lxi–lxii.the fallacy that logicians call a ‘circle’: Descartes is referring to the fallacyknown as the petitio principii (where the conclusion is presupposed in thepremiss). On circularity of argument, see above, note to p. , ‘comesfrom Him’, and Introduction, pp. lv–lvi.as empirical evidence: expérience: on this term, see above, note to p. ,‘many experiences’.

no apology for their being new: in an age in which reverence for ancient

learning underpinned much ‘scientific’ activity, this is a bold statement ofindependence.

. . . only by the books of the ancients: there is an echo here of a phrase usedto justify ‘the liberty of philosophizing’ (‘nullius addictus in verbamagistri’): see Introduction, p. xxviii.

useful to some by harming others: Gilson, Discours, , says that Descarteshas military engineering in mind here.

INDEXNote: the footnotes to the Introduction are indexed by note number, thus xxxi n.22; theExplanatory Notes are indexed by page number, thus 75n.

accommodation principle xxxiAdam, Charles, and Tannery, Paul xxxvii

n.26alchemy xiii, xxi, 10, 66n., 79n.Alexander of Aphrodisias lviialgebra lxiii, 16–17, 19animals: as machines xix, 46–8, 78n.; and

man lviii–lix, 3, 5, 39, 46–8; souls 48Anselm of Canterbury, St lvii, 74–5n., 76n.Apelles (Greek painter) xlviii, 65n.Aquinas, St Thomas x, lvii, 72n., 75n., 77n.Aristotelianism vii, xxii, xxiv, xxvii, xxxviii,

lvi, lxviii, 76n.Aristotle xxvi, xxxi, l–li, 78n.; and

knowledge liii, 57–8, 76n.; and the soullvii, 78n.; De anima 71n., 78n.; Deinterpretatione 76n.; Metaphysics 69n.;Meteorology lx; On the Heavens 77n.;Physics 69n.; Posterior Analytics l,73n.; Prior Analytics 69n.; Topics68n.

Arnauld, Antoine lviii n.38, 74n.astrology xv, 10, 66n.astronomy x, xvi, xxv, xxviii–xlAugustine of Hippo, St xxxi, xxxiii, xlviii,

lvii, lvii n.38, 74n.Ausonius xiiiAverroes lvii

Bacon, Francis xv, l, 70n., 79n.Baillet, Adrien xi–xii, xiii, xviii, xix–xx,

67n.Barbarini, Matteo, see Urban VIII, PopeBeaugrand, Jean de xx, xliii–xlivBeeckman, Isaac xi–xii, xxxviii, xl, 68n.Bellarmino, Roberto xxixBérulle, Pierre de xvBerzelius, Jons Jacob xxiBible, interpretation xxx–xxxiii, xxxixblood, circulation xxvii, lix, 40–5body: as machine xxvii, lix, 46; and mind

liv, 29, 31, 48, 51, 68n.Boulliau, Ismaël xxxviiBourdin, Pierre 75n.Boyle, Robert lxiibrain lvi, 45

Bruno, Giordano xxix, lviiiBureau d’Adresse xxxix, xliv, lxiBurman, Frans lv

Calvin, Jean lxiii–lxivCampanella, Tommaso xxix–xxx, lviiiCardano, Girolamo xlvi, 70n., 74n.Cartesianism xvii, xxicause and effect lxi–lxii, 38, 53, 61–2certainty: in mathematics xv, 9, 19, 31; and

scepticism liv, 11, 20, 25–6, 29, 32Chanut, Hector-Pierre xixCharlet, Étienne ixchiromancy 66n.Christina, queen of Sweden xviii–xixCicero: De divinatione 68n.; Paradoxa

stoicorum 72n.; Tuscan Disputations 72n.Clavius, Christophorus 69n.cogito lv–lvi, lvii, 28–9, 74n.Collège de la Flèche ix, xiv, xlix, lxv, 66n.,

69n.Comments on a Certain Broadsheet

(Descartes) xvii‘common sense’ lvi, lxvi, 45, 62Compendium musicae (Descartes) xiiCopernicus, Nicolas xvi, xxviii–xxxi,

xxxiv–xxxixcosmology xvi, xxviii–xxxviiicreation 37–8, 52; ex nihilo xxviii, 75n.Croll, Oswald 72n.custom li–lii, 8, 11, 14, 21

de la Ramée, Pierre xlixDear, Peter 69n.Descartes, René: character xix–xxi; as

French hero xxii; intellectualautobiography xxv, xlvi, xlviii–xlix, 3–11,12–20; life viii–xix; noble status viii, xi,xli, 78n.; as writer lxiii–lxviii; see alsoDiscourse

desire, and will lii–liii, 23–4, 68n., 72n.Diogenes of Sinope 67n.Dioptrics (Descartes) xxiv, xxvi, xl, lx, 61–2,

73n.Discourse (Descartes): genesis xxiii–xxviii;

impact vii; and intellectual

81

Discourse (Descartes) cont.:autobiography xxv, xlvi, xlviii–xlix, 3–11,12–20; Latin translation xlviii, 65n.;metaphysics and epistemology liii–lviii,28–34; physics and physiology lviii–lix,35–49; precepts in philosophy and ethicsxlix–liii, 21–7; presentation of the projectxlv–xlviii, 50–63; publication xl–xliv

disputations 56doubt liv, 11, 20–7, 28–9dreams xii–xiii, xiv, xxiii, xlvi, 28, 32–4Drebbel, Cornelis lxiDu Vair, Guillaume liiidualism lxviDuhem, Pierre lxix

earth, movement xxviii–xleducation: curriculum ix–x, lxvi, 7–8, 14,

66n., 68n.; Jesuit ix–x, xlix, 7, 64–5n.Elizabeth, princess of Bohemia xviii, lxvii,

64n.Elzeviers (publishers) xli, xlii, xlivempiricism, English xxii, lxiiEpictetus, Enchiridion lii–liii, 66n., 71n.epistemology l–li, liii, 26–34Erasmus, Desiderius xlii, xlviessence lvi, lxvi, 29, 74n.ethics li–lii, lxx, 3, 21–5, 28evidence lxvi–lxviiexistence: of God xxv, lvii, lxvi, 3, 29–33,

48, 74–5n., 76n.; of self xxv, lv–lvi, lxvi,lxx, 3, 28–9

experience, see experimentexperiment xxv, xxxi, xlvii, 52–4, 59–60,

61

Fabricius ab Aquapendente, Hieronymusxxvi

Ferdinand II, Holy Roman Emperor xii, 12,67n.

Fermat, Pierre de xx, xlivfire xxvii, 37–8Foscarini, Paolo xxix, xxx–xxxifree-thinking xiv, xxxviii, lvii

Galen xlvi, 70n., 73n., 77–8n.Galilei, Galileo x, xxviii–xl, lxviii, 76n.;

Dialogue Concerning the Two Chief WorldSystems xvi, xxv, xxxiii–xxxiv, xxxviii,lxiv–lxv, 78n.

Garasse, François xlviGassendi, Pierre lix, 76–7n.geometry lix, 16–17, 19, 31

Geometry (Descartes) xxiv, xl, xlii, xliv, xlv,lxii–lxiii

Gibieuf, Guillaume xiv–xv, lxvGide, André lxiiGilson, Étienne 70n., 78n., 80n.God: and creation 37–8, 52; existence xxv,

lvii, lxvi, 3, 29–33, 48, 74–5n.; and naturallaws xxvii, 35–8; as perfect being lvii,29–34, 36

grace, divine 15, 21, 51, 68n.Guez de Balzac, Jean-Louis xi, xv, xvi,

xxiv–xxv, xlii, xlviii, lxiii

Harriot, Thomas lxiii, 70n.Harvey, William xxvii, lix, lxi, 42–3, 77n.heart xxvii, lviii–lix, 3, 39–45Heinsius, Daniel xliiHelena (maidservant) xvheliocentrism xxviii–xlHerbert of Cherbury, Edward Herbert,

Baron 65n.Hobbes, Thomas xxHooke, Robert lxiihuman nature, and animals lviii–lix, 3, 5,

39, 46–8humanism x, xlii, 64–5n., 66n.humours 44, 79n.Huygens, Constantijn xv, xl, xlii

ideas: and passions 45–6 and truth32–4

imagination lvi, 18, 32–4, 45–8, 65n.incontrovertibility l, 9, 17, 29, 31, 55induction 70n.Inquisition xvi, xxix–xxxi, xxxiii,

xxxv–xxxix; Index of Forbidden Booksxxii, xxix–xxx

intellect lvi; and body 31; and will 23–5,71–2n.

intuition liv–lvii, lxii, lxvi, lxx

Jesuits, and education ix–x, xvii–xviii,xxxviii, 66n.

judgement lii, 5, 14

knowledge l–li, liv, 8–11; andAristotelianism 57–8, 78n.; hypothetico-deductive method xiii, xxiii, li, lxii, lxx,16–20, 24–6, 61–2; and observation andexperiment xxv, xxxi, xlvii, li, 52–4,59–60; probable liv, lxvii, 23, 64n.,68–9n.; and senses lvi, lxvi, 28, 32–4, 45,53, 69n.

82

index

La Flèche, Collège de ix, xiv, xlix, lxv, 66n.,69n.

La Fontaine, Jean de 78n.language: and animals 46–8; vernacular

xxv, xxx, xxxviii, xliv, xlvii, 62–3law, natural xxvii, 35–8, 45Le Maire, Jean (publisher) xli–xlii, xlivLenoble, Robert xxxvii, n.26light, natural xiii, lxviii, 11, 24, 64n., 75n.Lipsius, Justus xlii, liii, 72n.Llull, Raymond xlix, 16logic: circular argument 61, 76n.; petitio

principii 79n.; regressus lxi–lxii, 80n.;syllogistic l, liii, liv–lvi, lxi–lxii, 16

Loyola, St Ignatius x, 71n.lungs 44Lycurgus 68n.

magic 10, 66n.Malebranche, Nicolas 78n.‘malin génie’ 73n.mathematics xlvii, 18; and certainty xv, 9,

19, 31; notation xlviii, lxiii, 19, 69n.matter, and thought liv, lvi, 65n.Maurice of Nassau xi–xiiMaximilian, duke of Bavaria xii, 67n.mechanics xvi, xxi, xlvii, lviii–lix; of the

heart 39–45medicine xvii, xlvii, lxx, 3, 51–2, 63meditation 23Meditations on First Philosophy (Descartes)

xvi–xvii, xli, xliv, xlviii, li, liii–lv, lvii–lviii,lxiv–lxv

memory lvi, lviii n.38, 19, 45, 65n.Mersenne, Marin xiv–xv, xx–xxi, xxv,

xli–xliv, lvii–lviii, 74n.; and Galileoxxviii, xxx–xl; New Questions xxxviii, xlv;Quaestiones celeberrimae in Genesimxxx–xxxiii; Theological Questionsxxxviii–xxxix, lxi

metaphysics xxv, xlvii, liii–lvi, lxx, 3; asprior to physics lxvi, 70n.

Meteorology (Descartes) xxiv, xl, lx–lxi, 73n.mind: and body liv, 31, 51, 68n.; and

reflexive thought 71n., 74n.Montaigne, Michel de viii; and animals

78n.; and custom lii, 67n., 71n.; Essaysxxv, xlviii, 64n., 65–6n., 67n., 68n.; andscepticism 73n.; and soul 74n.

Montesquieu, Charles Louis de Secondatxxii

Morin, Jean-Baptiste xv, xxiiimotion lviii–lix

movement, human 45–6Mydorge, Claude xiv

natural philosophy xii, xlvii, li, lviii, lxi–lxii,71n.; and education ix, n.1

nature, mastery over 51Naudé, Gabriel xv, xlii, xlviNetherlands, move to x, xv, 73n.Nicholas of Cusa 77n.Noël, Étienne xlix

observation xxv, xxxi, xlvii, li, 52–4,59–60

occasionalism 75n.occultism xiii, xxi, 7, 10, 72n., 77n.ontology li, 28–9oratory 8, 9

Paris, and free-thinking xiv, xxxviii, lviipassions liii, 45–6Passions of the Soul (Descartes) xviii, liii,

67n., 71n.patronage xi, xviiiperception xxvii, l–li, lviperfection lvii, 29–34, 36Personne de Roberval, Gilles xxPetit, Pierre xxphilosophy: analytical xxii, lxix; and

architecture lxiv–lxv, lxix–lxx, 12–14, 21,25–6; as journey lxvii–lxviii, 5, 8, 22–3;mechanical xvi, xxi, xlvii, lviii–lix;speculative, see Aristotelianism Aristotle;and theology 8, 65n.; see also naturalphilosophy

physics xvi, xxiii, xlvii, lviii–lix, 3, 51, 71n.;and certainty xv; and metaphysics lxvi,70n.; publication 55–61

physiology lx, 39–46Picot, Claude xviipineal gland lix, 65n.Plato 69n.plausibility 8, 10–11, 38, 56–7Plutarch 66n.poetry 8, 9Poitiers, University x, 66n.Pomponazzi, Pietro lviiprejudice l, 17Principia see Principles of PhilosophyPrinciples of Philosophy (Descartes) xvii, xl,

lix, 71n., 73n., 76n.Private Thoughts (Descartes) xxivprobability liv, lxvii, 23, 64n., 68–9n.proportions, in mathematics 18–19

83

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propositions: incontrovertible l; plausible 8,10–11, 38, 56–7

Protestantism xprudence lii, 68n.Pursuit of Truth (Descartes) 66n.

radicalism, and reason xxi–xxiiRatio studiorum ix, 66n.reading, aversion to xxiv, xxv, 26, 64n., 65n.reason xiii, xxiv, xlvii, lvi, 5–6, 11, 13–20,

34, 62; and animals 46–7; cultivation 24;and radicalism xxi–xxii

refraction xv, 72n.Regius (Roy), Henricus xvii, xx, lxi, lxvRegulae, see RulesRenaudot, Théophraste xxxixrhetoric 9Richelieu, Card. Armand du Plessis de xxx,

xxxix, 67n.Richeome, Louis lviiRivet, André xliiRodis-Lewis, Geneviève xixRoman Catholicism x, xvi, xxii, xxviii–xlRoy (Regius), Henrick de xvii, xx, lxi, lxvRules for the Direction of Our Native

Intelligence (Descartes) xiii, xxiv, lxvi,64n., 65n., 70n.

Saumaise, Claude de xix, xliiscepticism liv, 11, 20–7, 28–9Scheiner, Christoph xxxvischolasticism ix–x, 32, 36; and logic liv–lv;

opposition to lxv–lxvii, 56; and prejudicel–li; vocabulary xxvi, lx, 30, 65n., 79n.

science: and knowledge 54–5, 61–3;method xiii, xvii, xxiii, xxvi, xlix–l, lxx, 3;see also natural philosophy; physics

self, existence xxv, lv–lvi, lxv, lxx, 28–9self-sufficiency lii–liiiSeneca lxvii, 64n., 66n., 72n.Sennert, Daniel 71n.senses, and knowledge lvi, lxvi, 28, 32–4, 45,

53, 69–70n.sensus communis lvi, lxvi, 45, 62Silhon, Jean de xiv, lviisine law xv, 73n.Sorel, Charles xlv

soul: existence 32; immateriality xxviii, lvii,lix, 3, 29, 38–9, 48–9, 68n.; immortalityxxviii, lvii–lviii, 49

spirits, animal lix, 45–6status, noble viii, xi, xli, 78n.Stoicism lii–liii, 23–4, 67n.substance lxv, 29, 37supposition 17, 37, 38, 61–2

Telesio, Bernardino lviiitemperament 51theology, and philosophy 8, 65n.Thirty Years War 67n.thought: as illusory 28; and matter liv, lvi,

65n.; reflexive 71n., 74n.; and truth32–4; see also cogito

tides xxvii, xl, 37transubstantiation xxiiTreatise on Light (Descartes) xvi, 37Treatise on Man (Descartes) xvi, lviii, 78n.truth: and being 74–5n.; and ideas 32–4;

and plausibility 8, 56–7; see alsoknowledge

universe: hypothetical xxvii, xxxviii, 36–9;infinity 77n.

Universe, The (Descartes) xvi, xxiii,xxv–xxvii, xxxiv, xxxvii–xxxviii, lviii

Urban VIII, Pope xxx n.21, xxxiii–xxxiv

vernacular xxv, xxx, xxxviii, xliv, xlvii, 62–3Viau, Théophile de xivViète, François 69n., 77n.Villebressieu, Étienne de xvvirtue 8, 25Voet, Gijsbert xviiVoltaire (Jean-Marie d’Arouet) xxiiVossius, Gerard xlii

will: and desire lii–liii, 23–4, 68n., 72n.; andintellect 23–5, 71–2n.

Williams, Bernard viiWillis, Thomas lxiiwomen xviii, xxii, xliv

Zabarella, Jacopo lxviZuniga, Diego de xxx–xxxi

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